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2011 Super Outbreak

2011 Super Outbreak

The storm system responsible for the historic tornado outbreak on April 27
Type	Tornado outbreak Extratropical cyclone Flood
Duration	April 25–28, 2011
Highest winds	210 mph (340 km/h) (Hackleburg/Phil Campbell, AL EF5 on April 27)
Tornadoes confirmed	360 confirmed (Record for a continuous outbreak)
Max. rating1	EF5 tornado
Duration of tornado outbreak2	3 days, 7 hours, 18 minutes
Largest hail	4.5 inches (11 cm) in diameter in Saltville, Virginia, on April 27
Fatalities	324 (+24 non-tornadic), 3,100+ injuries
Damage	~$11 billion (2011 USD) (Costliest on record for a tornado outbreak)
Areas affected	Southern United States, Midwestern United States, Eastern United States
1Most severe tornado damage; see Enhanced Fujita scale 2Time from first tornado to last tornado Part of the tornado outbreaks of 2011

The 2011 Super Outbreak was the largest, costliest, and one of the deadliest tornado outbreaks ever recorded, affecting the Southern, Midwestern, and Northeastern United States and leaving catastrophic destruction in its wake. The event affected Alabama and Mississippi the most severely, but it also produced destructive tornadoes in Arkansas, Georgia, Tennessee and Virginia, and affected many other areas throughout the Southern and Eastern United States. In total, 360 tornadoes were confirmed by NOAA's National Weather Service (NWS) and Government of Canada's Environment Canada in 21 states from Texas to New York to southern Canada. Widespread and destructive tornadoes occurred on each day of the outbreak, with April 27 being the most active day with a record of 216 tornadoes touching down that day from midnight to midnight CDT (0500 – 0500 UTC). Four of the tornadoes were destructive enough to be rated EF5, which is the highest ranking possible on the Enhanced Fujita scale; typically these tornadoes are only recorded about once each year or less.

In total, 348 people were killed as a result of the outbreak, which includes 324 tornado-related deaths across six states and an additional 24 fatalities caused by other thunderstorm-related events such as straight-line winds, hail, flash flooding or lightning. In Alabama alone, 238 tornado-related deaths were confirmed by the Storm Prediction Center (SPC) and the state's Emergency Management Agency.

April 27's 317 fatalities were the most tornado-related fatalities in the United States in a single day since the "Tri-State" outbreak on March 18, 1925 (when at least 747 people were killed). Nearly 500 preliminary local storm reports were received for tornadoes over four days, including 292 in 16 states on April 27 alone. This event was the costliest tornado outbreak and one of the costliest natural disasters in United States history (even after adjustments for inflation), with total damages of approximately $11 billion (2011 USD).

Meteorological synopsis

This animation of satellite images from April 26 through the morning of April 28 shows the development of the weather system which spawned the tornadoes.

The outbreak was caused by a vigorous upper-level trough that moved into the Southern Plains states on April 25. An extratropical cyclone developed ahead of this upper-level trough between northeastern Oklahoma and western Missouri, which moved northeast. Conditions were similar on April 26, with a predicted likelihood of severe thunderstorms, including an extended threat of strong to violent long-track tornadoes throughout the afternoon and evening hours; mixed-layer CAPE values were forecast to be around 3000–4000 J/kg, around east Texas, Louisiana, and Arkansas. The storm mode on April 26 was predicted to include mostly discrete supercells during both the afternoon and the early evening, shifting over to a mesoscale convective complex, with more of a threat of damaging winds and hail during the nighttime hours.

As the storm system moved eastward toward the Ohio, Mississippi, and Tennessee Valleys on April 27, a very powerful 80–100 knot mid-level jet stream moved into the Ohio and Tennessee Valleys behind the trough and created strong wind shear, along with a low pressure center moving quickly northeastward across those areas on April 27. During the afternoon of April 27, CAPE values were estimated to be in the range of 2000–3000 J/kg across Louisiana and southern Mississippi, with the moderate instability moving northeastward across the southern Tennessee Valley; additionally, temperatures across the southeastern United States ranged from the 70s°F (mid-20s°C) to the lower 90s°F (near 35 °C). Helicity levels ranged from 450–600 m²/s², which supported some significant tornadic activity and strong to violent long-track tornadoes.

A total of 56 severe weather watches were issued by the Storm Prediction Center (SPC) over those four days in the outbreak area. This included 41 tornado watches — 10 of which were Particularly dangerous situation (PDS) watches, and 15 severe thunderstorm watches. The SPC assigns numbers to each severe weather watch issued starting at the beginning of each year; the organization unscessfully used two of their allocated watch numbers during this outbreak (numbers 208 and 209).

April 25

A large area of possible severe storms for April 25–27 was forecast as the Storm Prediction Center (SPC) issued a moderate risk of severe weather for three consecutive days, centered over Arkansas through Tennessee. At 3:25 p.m. CDT (2025 UTC), the SPC issued a Particularly dangerous situation (PDS) tornado watch for much of Arkansas and parts of Missouri, Oklahoma, Texas, and Louisiana. By the evening hours of April 25, multiple tornadoes had been reported across a few states, some of which caused significant damage in Arkansas. An intense supercell thunderstorm tracked near the Little Rock area and a tornado emergency was declared for the city of Vilonia. A large EF2 wedge tornado struck the town, subsequently causing severe damage and killing four people. A strong EF3 tornado had also struck the Hot Springs Village area earlier that evening; that tornado caused severe damage and resulted in one death. Later that evening, Another EF2 tornado caused extensive damage to both a school building and Little Rock Air Force Base as well. Severe flooding continued across a large area from the Red River valley to the Great Lakes. A total of 42 tornadoes and four tornado-related deaths were confirmed on the 25th.

April 26

A high risk of severe weather was issued for April 26 for portions of Louisiana, Arkansas, Oklahoma, and Texas along and near the Interstate 30 corridor as conditions became even more favorable for extreme weather. A large PDS tornado watch with very high possibilities for tornadoes was issued for that same area that afternoon. Widespread tornado warnings were then issued in that area later that evening.

An upper-level negatively-tilted trough with two embedded shortwaves generated two surface lows that propagated generally east. One of the surface lows tracked northeast along the Mississippi River into Wisconsin as it occluded. Tornado watches were issued for the Lower Great Lakes during the afternoon hours as supercell thunderstorms developed along the warm front lifting north across central Michigan. Two tornadoes touched down in Michigan and caused damage to farm structures. Further east, severe thunderstorms caused scattered wind damage and large hail across Pennsylvania and New York. Two-inch-diameter hail was reported in Lock Haven, Pennsylvania. An isolated supercell moved across Central New York throughout much of the afternoon, producing golf ball-sized hail in Syracuse and spawning a very brief EF1 tornado in Verona Mills, which primarily caused damage to tree. Another tornado — this one being in Gilbertsville — caused significant damage to a school's athletic field.

The second surface low corresponded to an area of strong upper level divergence ahead of the downstream shortwave. As the low formed across Texas and deepened while moving east, a tightening pressure gradient force further strengthened the low-level jet, therefore creating a broad warm sector across the southeastern states. This also generated stronger wind shear, providing better organization for the supercell storms as a result. Numerous tornadoes touched down across several states, including Texas, Louisiana, Arkansas. Most of those tornadoes were weak, but a few of them caused considerable damage. A long-tracked wedge tornado caused EF2 damage in rural portions of Texas and Louisiana. An EF3 tornado destroyed multiple structures and caused severe damage at Fort Campbell, Kentucky as well. A total of 55 tornadoes were confirmed the 26th, although no fatalities occurred.

April 27

Significant severe weather was ongoing early on April 27 and continued for the entire day virtually unbroken. For the second day in a row, the SPC issued a high risk of severe weather for the Southern United States. Later that morning, the SPC even increased the probability for tornadoes to 45 percent along a corridor from Meridian, Mississippi, to Huntsville, Alabama, an extremely rare issuance exceeding the high risk standards. Conditions became increasingly favorable for tornadoes during such an extreme tornado outbreak.

Morning squall lines

During the early morning hours, a cold front with several embedded low pressure areas extended from east Texas northeastward into the Ohio River Valley. An upper-level disturbance that had moved across the frontal boundary the previous evening sparked an area of thunderstorms that morphed into a squall line. This line of severe thunderstorms would develope tornado actitvity from the evening on April 26 into the late morning of April 27. Early in the morning, the squall line, packing straight-line winds and numerous embedded tornadoes, moved through Louisiana and Mississippi before proceeding to affect North and Central Alabama and parts of Middle and East Tennessee. The line strengthened as it moved through Alabama, partially due to a high amount of low-level moisture from the Gulf of Mexico and increasing wind shear.

Many of the tornadoes embedded in this initial squall line were weak, even though several were strong and caused such significant damage. An EF3 caused major damage to homes in Coaling, Alabama, an EF2 and an EF3 produced severe damage and a fatality near Eupora, Mississippi. Another EF3 resulted in heavy damage in downtown Cordova, Alabama, which was struck by a deadly EF4 tornado later that afternoon. One embedded cell that began in Cullman County, Alabama produced a long-tracked EF2 that struck the town of Hanceville, killing one person. That cell would go on to produce over ten tornadoes (mostly EF1s) to the northeast in Marshall County and another EF1 in Dade County, Georgia. The initial storms caused widespread power and telephone line outages across Alabama and Tennessee. This line of storms also caused some NOAA weather radio transmitter sites to stop functioning for the remainder of the outbreak. Because of this, many people were without power and had no warning of any approaching tornadoes later that day.

From the late morning to the early afternoon, another squall line moved through northern parts of Mississippi and Alabama as high wind shear and low-level moisture persisted. However, this time several discrete supercells developed along and in front of the line, spawning seven weak tornadoes across Morgan, Limestone, and Madison Counties in northern Alabama around noon that day.

Afternoon supercells

Extremely deep ground scouring near Philadelphia, Mississippi caused by a fast-moving EF5 tornado that killed three people.

The most intense supercells of the outbreak developed shortly after noon in Mississippi and began tracking eastward. During the early afternoon, as wind shear and low-level moisture continued to dramatically increase, a tornado emergency was declared for Neshoba County, Mississippi, as a large tornado was reported on the ground by both storm spotters and a camera atop a television tower from ABC affiliate WTOK-TV (channel 11) in Meridian, Mississippi. This powerful EF5 tornado caused incredible damage northeast of Philadelphia, Mississippi, where pavement was torn off from roads, vehicles were thrown, and the ground was scoured out to a depth of 2 feet (0.61 m) by the tornado. Three people died when a mobile home was thrown 300 yards (270 m) into a wooded area, obliterating it in the process. Another very long-tracked EF4 tornado passed near the town of Enterprise, Mississippi, killing seven people before crossing into Alabama and eventually dissipating. Responding to the high risk issued by the SPC and the already unstable atmosphere expected to become even more unstable throughout the afternoon hours, a PDS tornado watch was issued at 1:45 p.m. CDT (1845 UTC) for much of Alabama and portions of Mississippi, Tennessee, and Georgia. A widespread complex of supercell storms overspread the states of Mississippi and Alabama and violent tornadoes began rapidly touching down as the evening progressed. Four tornadoes were officially rated as EF5's on the Enhanced Fujita scale that day. One of those EF5's struck the town of Smithville, Mississippi, where many well-built brick homes were reduced to bare slabs, numerous hardwood trees were completely debarked, and an SUV was hurled half a mile into the top of the town's water tower, subsequently leaving behind a visible dent. Another long-tracked EF5 wedge tornado passed through rural portions of Alabama and Tennessee, becoming the deadliest tornado of the outbreak as it completely devastated the towns of Hackleburg, Phil Campbell, Mount Hope, Tanner, and Harvest, killing 72 people. This marks only the third day in history (April 3, 1974, and March 13, 1990) that there were more than two F5/EF5 tornadoes reported.

The tornadoes continued tracking through central Alabama that afternoon and into the early evening hours. A dangerous and destructive tornado struck the city of Cullman, Alabama at around 3:00 p.m. CDT (2000 UTC). This large, multiple-vortex tornado was captured on several tower cameras from television stations, such as Fox affiliate WBRC (channel 6) and ABC affiliate WBMA-LD/WCFT-TV/WJSU-TV (channels 58, 33, and 40) both out of Birmingham. The tornado caused extensive destruction in the city's downtown area; it was ultimately rated an EF4. The final damage count was 867 residences and 94 businesses in Cullman, and six people died. The town of Cordova, Alabama, which had already been damaged by an EF3 tornado from the initial round of storms, was struck by an EF4 tornado that killed 13 people. Two violent EF4 tornadoes also ripped through Jackson County, Alabama, one of which caused a fatality near Bridgeport while the other passed near Pisgah and into Georgia where it caused major damage in Trenton and killed 14 people. At around 5:10 p.m. CDT (2210 UTC), a very large and exceptionally destructive tornado struck Tuscaloosa, Alabama and about 40 minutes later, that same tornado struck the northern suburbs of nearby Birmingham. A tornado emergency was issued for both cities, along with many other cities that day. Many local television stations, including WBRC and WBMA-LD/WCFT/WJSU, as well as CBS affiliate WIAT (channel 42), broadcast live footage of this long-tracked tornado in both Tuscaloosa and Birmingham. A debris ball was observed by the Birmingham NEXRAD, indicating that the tornado was causing extreme damage. This tornado killed 64 people and caused extensive devastation in densely populated areas, and the tornado struck several of the same small communities as the April 1956 F4, the April 1977 F5 and the April 1998 F5 tornadoes that hit portions of the Birmingham area. The supercell that procured that the Tuscaloosa/Birmingham EF4 tornado originated in Newton County, Mississippi. The supercell also produced an EF4 tornado later that evening that killed 22 people and struck the Ohatchee, Alabama area and eventually crossed into Georgia, causing additional damage near Cave Spring before dissipating. Further to the south, a mile-wide EF3 tornado killed 7 people in mostly rural areas and caused major damage in the small town of Eoline. The final EF5 tornado of the day caused remarkable damage in and around the town of Rainsville, Alabama, killing 25 people before crossing into Georgia and dissipating. Tornadoes continued touching down further to the northeast as the sun set, particularly in Georgia. This included a long-tracked EF4 that caused major damage in Ringgold, Georgia, Apison, Tennessee, and Cleveland, Tennessee, killing 20 people along the path. After dark, violent tornadoes continued to touch down, and a nighttime EF4 tornado destroyed many lakeside homes at Lake Martin in eastern Alabama, killing seven people. Additional strong nighttime tornadoes occurred in Georgia, including an EF3 that killed two people in Barnesville, and another EF3 that destroyed multiple homes and killed one person at Lake Burton.

Continued activity farther east

Powerful tornadoes touched down across Tennessee as well that evening. A violent EF4 struck the community of New Harmony, Tennessee, where homes were leveled, vehicles were tossed, and four people were killed. Two EF3 tornadoes crossed paths in Greene and Washington counties (coming a couple hours apart), resulting in eight fatalities. The rural communities of Horse Creek and Camp Creek suffered major damage from those tornadoes late that evening. A very large EF4 wedge tornado leveled a mile-wide swath of forest through 14 miles (23 km) of Great Smoky Mountains National Park. At Chilhowee Lake, large metal power line truss towers were torn and thrown from their concrete supports that they were anchored to.

A secondary area of severe weather also developed that afternoon and evening along the Interstate 81 corridor from central and northern Virginia northward through Maryland, Pennsylvania, and New York, continuing into early April 28. Many tornadoes touched down in this area as well. Most of these tornadoes were weak, though an EF2 tornado touched down near the town of Halifax, Virginia, and caused severe damage to homes in the area, resulting in one death. Tornado alerts were issued for Southern Ontario as far north as Ottawa as well; one tornado was later confirmed in Fergus, Ontario.

Map of all tornado (red), severe thunderstorm (yellow), and flood (green) warnings issued on April 27.

Overview

A statewide review by emergency management officials recorded 249 fatalities in Alabama, 23 of which were not tornado-related. Damage and power outages in the Huntsville area were so widespread that at one point over 650,000 people were out of power in the Tennessee Valley Authority system. The EF5 tornado that struck Hackleburg and Phil Campbell eventually damaged main power lines coming from Browns Ferry Nuclear Plant further to the northeast. These towers were the main supply of electrical power to much of North Alabama and some were without power for two weeks. The tornado just missed the Limestone Correctional Facility, which less than a year later would be struck by another tornado.

The Storm Prediction Center received 292 reports of tornadoes in the preceding 24 hours. It broke the record for the most tornado touchdowns in 24 hours with 219 in the United States from midnight to midnight CDT (0500 – 0500 UTC) breaking the 24-hour record of 147 (in both totals, excluding confirmed tornadoes outside the United States that were part of the outbreak) set by the 1974 Super Outbreak. Of those 219 tornadoes, 59 touched down in Alabama and 79 hit the ground in Tennessee, accounting for well over half of the tornadoes that touched down on April 27. On April 27 alone, the National Weather Service in Huntsville, Alabama issued 92 tornado warnings, 31 severe thunderstorm warnings, and seven flash flood warnings.

April 28

Tornado watches were issued for the Atlantic coast from Pennsylvania to Florida at the start of the day and continued through the morning and early afternoon, but tornadoes were forecasted to generally be weaker and more isolated. Despite this, the secondary portion of the outbreak that had begun producing scattered tornadoes throughout the Mid-Atlantic and East Coast regions the previous evening intensified during the early hours of the morning, producing numerous tornadoes in Pennsylvania, New York, Virginia, North Carolina, South Carolina, Georgia, Florida, and Maryland. While most were weak, some of the tornadoes that struck portions of Virginia, New York, and Pennsylvania were strong. Although tornado watches were issued, no tornadoes were spotted in New Jersey or Washington, D.C. In the wake of the tornadoes and severe thunderstorms, widespread flooding hit the Midwest, South, and Eastern Seaboard, with extensive flood and flash flood warnings issued. One particularly damaging and deadly EF3 tornado struck the town of Glade Spring, Virginia very early in the morning, where three people died. The last tornadoes of the outbreak touched down that afternoon in eastern North Carolina, which was hard hit in the April 16 outbreak, though the tornadoes that impacted the area this time around were weak. The system moved out into the Atlantic Ocean that evening, with the exception of isolated thunderstorms over central Florida that night into April 29, although there were no tornadoes then.

Notable tornadoes

May 28 event

Confirmed tornadoes by Enhanced Fujita rating

EFU	EF0	EF1	EF2	EF3	EF4	EF5	Total
0	20	33	7	4	3	1	68

EF#	Location	Duration (local time)	Description
Iowa
EF1	W of Victor to N of Ladora	4:51-4:59 PM	Elephant trunk tornado caused considerable roofing damage to homes, businesses, and warehouses, snapped several dozen trees, and blew over a number of trailers at Victor Manufacturing.
EF0	N of Rowan	5:04-5:07 PM	Intermittent rope tornado snapped tree branches and caused roofing damage to mobile homes.
EF1	E of Gladbrook to E of Zaneta	5:22-5:34 PM	Farmsteads had roofing removed. Wooden paneling was removed from the walls of barns and tractors were rolled.
EF1	S of Park View to N of McCausland	5:49-5:53 PM	Cone tornado snapped hundreds of tress and uprooted several dozen. Homes and small shops had their roofing stripped, leaving internal decking exposed.
EF0	S of Alpha	6:07-6:09 PM	Brief elephant trunk tornado caused no damage.
EF3	W of Aplington to E of New Hartford	6:18-6:35 PM	4 deaths - A high-end EF3 wedge tornado followed a similar path to the 2008 EF5 Parkersburg-New Hartford tornado, demolishing several hundred homes along its path, tossing tractors up to 70 yards, partially debarking small trees, and mangling transmission towers.
EF1	Buffalo Center to N of Thompson	6:39-6:45 PM	High-end EF1 cone tornado caused severe roofing damage to around 300 homes, blew over several trees, and toppled trailer homes.
EF0	W of Harcourt to W of Dayton	6:40-6:42 PM	Brief rope tornado snapped tree branches and caused minor roofing damage to homes.
EF2	W of Gilbert to N of Randall area	6:49-7:01 PM	A large cone tornado completely removed the roofing from around 180 homes; transmission towers sustained minor damage, and several vehicles including a large pickup truck were tossed up to 40 yards
EF1	S of Lincoln to E of Buckingham	7:12-7:19 PM	An elephant trunk tornado stripped roofing from several homes and barns, flipped small cars, and caused minor damage to large oil storage tanks.
EF1	S of Huxley to E of Nevada	7:33-7:43 PM	Fast-moving cone tornado caused severe roofing damage to homes, barns, and shops. Two radio masts sustained minor damage as well.
EF1	S of Humboldt to N of Ravenna	7:59-8:04 PM	Stovepipe tornado damaged farm buildings, trees, power poles, and crops along its path. Numerous trees were also snapped or uprooted.
EF4	W of Fenton to W of Alexander	8:06-8:44 PM	9 deaths- See section on this tornado. A large cone tornado completely leveled over 750 homes and demolished industrial buildings, with the steel roofing and walls of warehouses being shredded and crumpled. Additionally, tractors were tossed in excess of 200 yards and trees were completely debarked and denuded.
EF1	S of Calmar to N of Decorah	8:44-8:53 PM	A thick rope tornado struck multiple farmsteads, causing minor damage to farmhouses and heavily damaging or destroying multiple outbuildings. Trees were snapped and horse trailers were moved and pushed over.
EF1	E of Monticello to E of Cascade	8:51-9:01 PM	Narrow stovepipe tornado stripped roofing from over 150 houses, demolished around two dozen mobile homes, and toppled a large trailer.
EF0	N of Wilton	9:11-9:14 PM	Rope tornado caused minor damage to small tool sheds and removed shingles from the roofing of a barn.
Minnesota
EF1	N of Searles to E of Nicolette	4:37-4:50 PM	Houses sustained considerable roofing damage; parked cars were flipped, and unanchored grain bins were toppled (two were broken open).
EF0	W of Morristown	5:08-5:11 PM	Narrow elephant trunk tornado caused no reported damage.
EF2	S of Norcross to N of Elbow Lake	5:26-5:39 PM	Roofing was completely removed from over 400 houses, including six new and well-built brick homes. Additionally, cars and pickup trucks were tossed, and a log inn was mostly demolished.
EF0	W of Kerkhoven to E of Murdock	5:44-5:46 PM	A thin rope tornado caused minor roofing damage to houses and partially demolished tool sheds and outbuildings.
EF3	E of Ihlen	6:01-6:14 PM	A brief but intense stovepipe tornado demolished farmsteads and leveled several barns. Tractors were tossed up to 60 yards and transmission towers sustained considerable damage. Minimal ground scouring occurred over a portion of the tornado's track.
EF1	Hazel Run area	6:20-6:23 PM	Several homes and a church sustained considerable roofing damage from this heavily rain-wrapped tornado. Eight people were injured.
EF1	W of Arlington to N of Volga	6:21-6:26 PM	Farmhouses sustained considerable roofing damage from a high-end EF1 cone tornado. The same supercell would later produce the EF5 Marshall tornado and the EF4 Winona tornado.
EF5	SW of Ivanhoe to N of Lucan	6:59-7:43 PM	46 deaths - See section on this tornado. Wedge tornado achieved a peak width of 1.6 miles. Homes in residential districts of Marshall were swept away with carpeting ripped from the foundations and plumbing uprooted. A chemical plant was also swept away, and the main building of the Southwest Minnesota State University was twisted almost completely off its foundation. Additionally, a large irrigation system was tossed intermittently for six miles, and crops were shredded down to stubble.
EF1	S of Revere to E of Sanborn	7:16-7:24 PM	Heavy farm equipment was moved around and a few trees were damaged by a rain-wrapped tornado.
EF0	W of Red Wing	7:33-7:36 PM	An intermittent elephant trunk tornado caused no damage.
EF0	E of Le Center	7:49-7:51 PM	A slow-moving, narrow stovepipe tornado produced no reported damage.
EF2	S of Dexter to N of Grand Meadow	8:01-8:14 PM	A large cone tornado caused considerable damage in both towns, with several houses heavily damaged, the roofing partially removed from three warehouses, and mobile homes and grain bins destroyed.
EF4	W of Dover to S of Tamarack	8:12-8:58 PM	17 deaths- See section on this tornado. A high-end EF4 wedge tornado leveled several hundred homes and swept away two small, unanchored houses. Dozens of vehicles were tossed, including a large RV which was thrown 210 yards. A recycling plant in Winona was completely demolished with portions of steel roofing being tossed up to 500 yards. Small trees were debarked and some pavement scouring occurred. A large tugboat was flipped as the tornado reached the Mississippi River.
EF0	Prior Lake area	9:06-9:11 PM	A metal shed was damaged and trees were uprooted by a heavily rain-wrapped tornado.
Missouri
EF0	Laredo area	5:56-5:59 PM	Narrow cone tornado caused minor roofing damage to homes and small shops.
EF0	W of Graham	6:10-6:12 PM	Brief rope tornado caused no damage.
EF1	W of Calhoun to S of Bryson	6:36-6:48 PM	Fast-moving elephant trunk tornado caused severe roofing damage to several brick homes, barns, and a police station. Tractors were blown over, parked cars were flipped, and tree branches were snapeed.
EF2	S of Osgood to N of Newtown	7:04-7:23 PM	This high-end EF2 wedge tornado, 1,150 yards at its peak, completely demolished around 20 mobile homes, stripped the roofing from brick houses, toppled an empty passenger train car, and damaged transmission towers.
EF1	E of Lebanon to S of Stoutland	7:29-7:40 PM	A strong stovepipe tornado toppled an 11-ton marble statue, removed large sections of wooden panelling from barns, and pushed a van and a garbage truck from a highway.
EF1	S of Reeds Spring to N of Highlandville	8:06-8:19 PM	This high-end EF1 cone tornado demolished five mobile homes, caused severe roofing damage to several frame houses, flipped and rolled parked cars and vans, and rolled a propane tank around 20 yards.
EF1	W of New Cambria to N of Ethel	8:59-9:07 PM	Several barns were stripped of their roofing and had sections of wooden paneling removed from their walls.
Nebraska
EF4	E of Hebron to Daykin to S of Western	3:37-3:59 PM	Highly visible elephant trunk tornado completely leveled well-built brick houses, tossed a pickup truck around 400 yards, toppled a radio mast and debarked several dozen trees.
EF0	S of Halsey	5:09-5:12 PM	Brief, intermittent cone tornado caused minor damage to barns and farmhouses.
EF1	W of Pleasanton to W of Ravenna	5:22-5:29 PM	Houses sustained severe roofing damage, parked cars were flipped, and trees were snapped and uprooted by this heavily rain-wrapped tornado. Around 20 people were injured.
EF1	S of Johnstown to W of Ainsworth	5:41-5:46 PM	Heavily rain-wrapped tornado; frame homes and barns sustained considerable roofing damage; three pickup trucks were flipped, and trees were snapped.
EF0	Elwood area	6:07-6:09 PM	Rope tornado caused minor damage to homes and shops.
EF1	S of Hildreth to N of Upland	6:18-6:23 PM	Elephant trunk tornado stripped roofing from homes and small businesses; mobile homes were mostly demolished; a Wal-Mart lost a portion of its roofing, and a propane tank was rolled around 20 yards.
EF1	N of Burwell to N of Deverre	6:39-6:46 PM	Narrow stovepipe tornado caused roofing damage to homes and shops; small greenhouse buildings were demolished, and tractors were rolled over.
EF0	W of Lindy to N of Crofton	6:57-7:00 PM	Narrow cone tornado caused no damage.
EF0	Sarben/Paxton area	6:58-7:01 PM	Rain-wrapped tornado; minor roofing damage to homes and businesses was reported.
EF2	E of Holderidge to N of Minden	7:31-7:44 PM	1 death - Cone tornado caused severe damage to around 200 buildings; roofing was completely removed from well-built brick houses, and transmission towers sustained minor damage.
EF1	Springview to S of Burton	7:49-7:55 PM	Rope tornado damaged several farmsteads, with a barn completely destroyed at one of them. Trees in a shelter belt were also heavily damaged.
EF1	N of Hazard to N of Ravenna	8:17-8:22 PM	Sheds were destroyed and barns were severely damaged. Numerous large trees were snapped and uprooted.
EF3	W of Stromsburg to W of Shelby to N of Rising City	8:48-9:13 PM	A large stovepipe tornado demolished several dozen homes including a large and newly-built brick house. Twenty power poles were snapped along the track, one of which was pulled out of the ground. Additionally, around a dozen hay bales weighing up to 1,500 lb were blown away and not recovered.
North Dakota
EF0	E of Kathryn	4:54-4:57 PM	Narrow stovepipe tornado caused no damage.
EF1	Wishek area	5:18-5:24 PM	Elephant trunk tornado damaged the roofing of roughly 150 buildings and uprooted small trees.
EF1	Linton to N of Hazelton	5:56-6:05 PM	Rope tornado caused severe roof damage to houses and shops, overturned several trailers, and tossed a large stack of wood pallets.
EF1	W of Edgeley to W of Lamoure	6:26-6:36 PM	A high-end EF1 elephant trunk tornado caused roofing damage to homes, warehouses and a grocery store and pushed moving cars off of roads.
South Dakota
EF3	W of Orient to W of Doland	5:24-6:31 PM	3 deaths - This large wedge tornado demolished 65% of buildings in the town of Redfield and ripped grain silos from their foundations. One survey found EF4 damage to a house in Redfield; rating was not upgraded due to the fact that the house was likely poorly anchored.
EF1	W of Parade to W of Ridgeview	5:37-5:44 PM	A high-end EF1 elephant trunk tornado caused roofing damage to homes, warehouses and a grocery store and pushed moving cars off of roads.
EF1	Timber Lake area	5:59-6:05 PM	Houses, shops, and warehouses sustained severe roofing damage from this heavily rain-wrapped tornado. Radar failed to identify a hook echo; no tornado warning was issued. Around 60 people were injured.
EF1	W of Pukwana to E of Kimball	6:31-6:40 PM	Barns had wooden paneling removed from their roofing and walls, and a moving van was rolled off a road into the ditch.
EF2	S of Presho to N of Kennebec	7:06-7:19 PM	Intermittent multiple-vortex tornado. Brick houses had their roofing completely removed and farmsteads were demolished.
Wisconsin
EF0	NW of Whitehall	7:39-7:44 PM	Damage to mobile homes and tree branches was reported.
EF1	S of Salem	8:11-8:16 PM	Rope tornado caused roofing damage to farmhouses and roadside shops.
EF2	W of Tell to E of Praag	8:30-8:41 PM	Cone tornado demolished several manufactured homes, tossed parked cars short distances, and rolled a cargo container several times.
EF1	S of Rock Falls to SE of Truax	8:56-9:13 PM	1 death - Stovepipe tornado caused significant roofing damage to homes and snapped and toppled numerous trees. 60 people were injured.
EF0	E of Ladysmith	9:25 PM	Brief multiple-vortex tornado caused no reported damage.
EF1	S of Park Falls area	9:33-9:39 PM	High-end EF1 elephant trunk tornado stripped roofing from houses, snapped several trees and flipped parked cars.
EF0	S of Cottonville area	9:46-9:48 PM	Minor roofing damage was reported from a brief rope tornado.
EF0	WNW of Westfield	10:04-10:07 PM	Cone tornado caused minor damage to tree branches and mobile homes.
EF1	SW of Bloomville to NE of Dudley	10:19-10:27 PM	Roofing was stripped from several hundred homes and businesses, and numerous trees were blown over. Around 30 people were injured.

Hackleburg–Phil Campbell–Tanner–Harvest, Alabama/Huntland, Tennessee

Main article: 2011 Hackleburg–Phil Campbell, Alabama tornado

EF5 damage in Phil Campbell, with multiple homes swept away and grass scoured from hillsides.

This devastating, long-tracked, EF5 wedge tornado was the deadliest of the outbreak. It first touched down in Marion County, Alabama about 5 miles (8.0 km) west-southwest of Hamilton around 3:00 p.m. CDT (2100 UTC) on April 27, leaving massive damage along its track. The storm would eventually reach the Hackleburg area, completely leveling many homes and businesses, including a large Wrangler, Inc. factory. Most of the structures in downtown Hackleburg were badly damaged and Hackleburg High School was destroyed. Well-built homes were wiped cleanly from their foundations, extensive wind-rowing of debris occurred, trees were completely debarked, and cars were thrown hundreds of yards. According to the American Red Cross, 75 percent of the town was destroyed. While initially rated as an EF3, the rating was increased to EF5 after further analysis of the damage, making it the first F5/EF5 tornado in Alabama since the Birmingham tornado of April 8, 1998.

Soon after crossing into Franklin County, the town of Phil Campbell experienced significant devastation of the same magnitude as Hackleburg. Numerous homes, some of which were well-constructed, were swept away as the tornado tore through town. At least three churches along the path sustained significant damage, with one church in the town being completely destroyed and having only the foundation slab remaining. Multiple mobile homes throughout the path were completely destroyed, and their mangled frames were tossed at least 25 to 50 yards (23 to 46 m). Cars were tossed and destroyed throughout the path of the tornado, with one car wrapped around a debarked tree. A 25-foot (7.6 m) section of pavement was torn from a road in this area as well. The most intense damage along the path occurred northeast of Phil Campbell in the rural community of Oak Grove, where vehicles were carried long distances and mangled beyond recognition, large trees were completely debarked, and large brick homes with extensive anchoring were obliterated with the debris wind-rowed hundreds of yards away. The tornado continued into Lawrence County, impacting the Mount Hope community, where significant devastation was incurred to single-family homes and a restaurant. Nothing but the foundation and a pile of debris remained at the restaurant site, and a small portion of the restaurant's foundation slab buckled.

Large area of pavement scoured from a road in Phil Campbell.

The tornado moved northeast, producing EF3 damage in and around Langtown. The tornado re-intensified to EF4 strength as it passed near Moulton and Trinity, debarking trees, mangling, and leveling homes. It then continued through the northwest corner of Morgan County, crossed Wheeler Lake, and moved into Limestone County, coming within 2 miles (3.2 km) of Browns Ferry Nuclear Power Plant. The tornado caused power outages in the area, and the plant had to be shut down. The tornado continued towards the small community of Tanner. Tanner experienced a large swath of EF4 damage and a narrow corridor of "high-end EF4 to near-EF5 damage". The storm "completely wiped clean" several well constructed homes with anchor bolting. As the storm crossed U.S. Highway 72 in eastern Limestone County, the tornado destroyed a Doppler radar operated by NBC affiliate WAFF (channel 48) and continued into East Limestone, a heavily populated area of Limestone County where homes in multiple subdivisions were damaged or destroyed at high-end EF3 strength. As the storm crossed into Madison County, it approached the densely populated suburban communities of Harvest and Toney, where it either damaged or destroyed hundreds of homes, especially in the Anderson Hills and Carter's Gin subdivisions. Many homes were reduced to rubble, and the damage in this area was rated mainly EF3 with a small pocket of EF4 damage in Harvest. The tornado completely destroyed a Piggly Wiggly grocery store in Harvest and severely damaged a convenience store and local bank, which was shut down for months following the event. The storm progressed across Pulaski Pike in northwest Madison County, damaging many homes. In all, hundreds of homes received moderate to major damage along the path from Limestone to Madison County with many of these being total losses.

The tornado then moved into Tennessee and continued south of Huntland. Isolated and minor EF0 to EF1 damage was noted through most of its path in Tennessee. Widespread damage to trees and outbuildings occurred in this area. The worst damage, however, was to a cinder block utility building and was rated lower-end EF3. Most of its roof was removed, with over half of its downwind wall pushed outward. The tornado eventually dissipated east of Huntland.

In total, this tornado killed 72 people, all in Alabama. This made it the deadliest single tornado ever to strike the state of Alabama as well as (at the time) the deadliest in the United States since the 1955 Udall, Kansas tornado that killed 80 people. In addition to being the deadliest, this tornado also had the longest track of any tornado in the outbreak, with its path extending 132.1 miles (212.6 km) across Northern Alabama and into Tennessee.

Smithville, Mississippi/Shottsville, Alabama

Main article: 2011 Smithville, Mississippi tornado

This extremely violent EF5 wedge tornado, with estimated winds of up to 205 mph (330 km/h), struck the town of Smithville, Mississippi, at 3:47 p.m. CDT (2047 UTC) on April 27, resulting in catastrophic damage and numerous fatalities. The tornado began 3 miles (4.8 km) west-southwest of Smithville along the Tennessee–Tombigbee Waterway near the Glover Wilkins Lock at 3:42 p.m. CDT (2042 UTC), snapping numerous trees near the Smithville Recreation Area. The tornado then rapidly intensified as it approached town, reaching EF5 intensity. As the storm crossed Davis Road South, the ground was deeply scoured in a nearby field. The tornado swept away numerous homes and structures as it moved northeast, following Highway 25. A semi-truck was thrown a considerable distance and destroyed in this area, and at one residence that was swept away, part of the concrete foundation slab was pulled up and dislodged slightly. A large brick funeral home was reduced to a bare slab as the tornado exited at the northeast side of town, with the debris scattered and wind-rowed into an adjacent wooded area. Nearby granite tombstones were blown over in the opposite direction of the tornado's passage. Overall, the tornado destroyed 117 structures in Smithville and damaged 50 others, killing 16 people. The tornado weakened as it continued through rural areas northeast of town and moved into Itawamba County, where it downed numerous trees and power lines and caused roof damage to a house before exiting the county.

The tornado continued across the Alabama state line into Marion County, where it caused EF1-strength damage near Bexar. Continuing northeast, the tornado re-intensified as it struck the rural community of Shottsville at high-end EF3 intensity, where homes and mobile homes were destroyed and seven people were killed, and it produced additional high-end EF3 damage as it continued north of Hamilton. More structures were impacted as the tornado approached and crossed into Franklin County. The tornado then dissipated near the town of Hodges at 4:23 p.m. CDT (2123 UTC). The damage path was 37.3 miles (60.0 km) long and 3⁄4 mile (1.2 km) wide at its widest point, and it killed a total of 23 people along its path. 137 other people were injured.

Pisgah–Flat Rock–Higdon, Alabama/Trenton, Georgia

Aerial view of damage in Trenton.

This multiple-vortex EF4 tornado devastated portions of Jackson and DeKalb counties in Alabama, as well as Dade and Walker counties in Georgia along a 47-mile-long (76 km) path, killing 14 people and injuring at least 50 others.

The tornado touched down north of Section, initially producing EF0 to EF1 tree damage. The tornado rapidly intensified to low-end EF4 strength as it passed northwest of Pisgah and Rosalie, destroying numerous mobile homes and block foundation homes, scattering the debris hundreds of yards and killing three people. Thousands of trees were snapped and debarked, vehicles were thrown up to 50 yards in different directions, and multiple barns and chicken houses were heavily damaged, along with the roof of a church. As it passed near Flat Rock and Higdon, the tornado reached high-end EF4 strength, mowing down thousands of trees in this rural area. As the tornado struck a farm, a home and two chicken houses were completely obliterated and swept away. A heavy propane tank was lofted and thrown 100 yards from one of the chicken houses, and 19 cattle on the property were killed. Remarkably, a family of four taking shelter inside the house were completely unharmed. The tornado maintained EF4 strength as it tore through the rural community of Shiloh, sweeping away numerous mobile homes and block foundation homes and killing 5 people at that location. Thousands of trees were snapped, a log cabin was destroyed, livestock was killed, chicken houses were flattened, and a van was lofted and dropped into a field 400 yards away from where it originated. The tornado then crossed into Georgia and struck Trenton as an EF3, killing two people. Dozens of homes in Trenton were completely destroyed, 18 others sustained major damage, and tens of thousands of trees were downed in the area. A grocery store, two apartment complexes, and a funeral home were destroyed as well.

The tornado weakened to EF2 strength as it struck Flintstone further to the northeast, but still resulted in major damage. Numerous trees and power lines were downed, 7 homes were destroyed, 26 sustained major damage, and 35 sustained minor damage in the Flintstone area. The tornado continued northeast, weakening to EF0 strength and dissipating in Fort Oglethorpe.

Tuscaloosa/Birmingham, Alabama

Main article: 2011 Tuscaloosa–Birmingham tornado

Satellite image of the tornado's track through Tuscaloosa.

A large multiple-vortex wedge tornado touched down in rural Greene County, Alabama, and tracked across neighboring Tuscaloosa County, including the southern and eastern portions of Tuscaloosa at around 5:10 p.m. CDT (2210 UTC) on April 27. Debris from the tornado was reported to be falling from the sky across Birmingham over 20 miles (32 km) away in Jefferson County. Skycams operated by Tuscaloosa television station WVUA-CA (channel 7) as well as Birmingham Fox affiliate WBRC (channel 6), ABC affiliate WBMA-LD/WCFT-TV/WJSU-TV (channels 58, 33, and 40), and CBS affiliate WIAT (channel 42) captured live footage of the tornado as it struck Tuscaloosa; WIAT received multiple awards, including a regional Edward R. Murrow Award for "Outstanding Live Coverage" of the event). As the tornado traveled east to 35th Street and Kauloosa Avenue, the Tuscaloosa Environmental Services and Cintas facilities suffered severe damage. Numerous homes and apartment buildings in the Rosedale and Forest Lake neighborhoods, as well as a P&P Grocery store in Rosedale, were devastated. Several stores and restaurants in a business district at the intersection of McFarland Boulevard and 15th Street, near the DCH Regional Medical Center, were reduced to rubble. Buildings on 35th Street, between Interstate 359 and Martin Luther King Jr. Boulevard, were also completely destroyed. The Alberta City neighborhood in eastern Tuscaloosa sustained catastrophic damage as numerous homes, apartment buildings, and a shopping center were completely leveled. Additional high-end EF4 damage occurred in the Tuscaloosa suburb of Holt further to the northeast, as several homes were leveled or swept away in that area. The tornado then exited the Tuscaloosa area and moved through dense forest towards Birmingham, downing and debarking thousands of trees. The University of Alabama suspended its operations, cancelled its softball and rowing competitions, cancelled its final exams period, and postponed its commencement until August 6.

Radar and velocity image of the supercell that produced the tornado at 22:10 UTC (5:12 p.m. CDT) as it struck Tuscaloosa, with a debris ball clearly visible.

The demolished Chastain Manor apartment complex in Tuscaloosa.

Many stations, including WIAT, WBMA/WCFT/WJSU, WTVY (channel 4) in Dothan and WSFA (channel 12) in Montgomery, showed television cameras capturing the event as the tornado moved east-northeast across the western and northern suburbs of Birmingham around 6:00 p.m. CDT (2300 UTC). Several suburbs in the area were severely damaged by the massive tornado as it tore through the west side of Birmingham, resulting in multiple fatalities. The suburbs of Concord, Pleasant Grove, and McDonald Chapel were devastated by the tornado as it moved northeast, flattening entire neighborhoods. As the tornado entered the Birmingham city limits, it devastated the Pratt City neighborhood, destroying numerous homes and apartment buildings. The tornado then struck the suburb of Fultondale, causing EF2 damage to homes and businesses before dissipating east of Fultondale. Surveys indicated high-end EF4 damage from the tornado in Birmingham's western suburbs.

The National Weather Service determined the path length of this violent tornado to be 80.7 miles (129.9 km) with a maximum damage path width of 1.5 miles (2.4 km). The tornado's most intense damage indicated peak winds of around 190 mph (310 km/h); therefore, it was given a final rating of EF4. Reports from Tuscaloosa indicated 44 people were killed, with an additional 20 deaths in Birmingham. Overall this tornado killed 64 people and injured more than 1500. President Barack Obama and First Lady Michelle Obama visited Tuscaloosa on April 29, taking a ground tour of some of the affected areas. Obama was quoted as saying that he has "never seen devastation like this." He stated further that he had already declared a federal state of emergency in Alabama.

Aftermath

Alabama Governor Robert J. Bentley declared a state of emergency in the state of Alabama on April 27, due to storm damage from severe thunderstorms earlier that day as well as forthcoming severe weather later that day. States of emergency were also declared in Arkansas, Kentucky, Mississippi, Missouri, Tennessee, and Oklahoma because of the flooding and tornadoes. Following the tornado outbreak on the evening of April 27, President Barack Obama granted a federal emergency declaration for the state of Alabama, giving federal assistance, including search and rescue assets, to the affected region.

More than 2,000 National Guard troops were deployed to Alabama, assisting local and state first responders in search and rescue efforts. President Obama visited the affected areas of Alabama on April 29. Also on April 29, he approved a federal disaster declaration for seven Mississippi counties: Clarke, Greene, Hinds, Jasper, Kemper, Lafayette, and Monroe. By the morning of April 30, the Alabama Emergency Management Agency had confirmed at least 45 storm fatalities in Tuscaloosa, but this was later corrected downward to 44. The tornado killed 64 people along its entire path.

Electricity outage

Storms through the area severely damaged Tennessee Valley Authority (TVA)'s power grid for transmitting electricity throughout the region. More than 300 power transmission towers, 120 feet (37 m) to 150 feet (46 m) tall, were destroyed in the storms, some "twisted like bow ties" according to National Weather Service meteorologist Eric Holweg. The towers supported some 90 transmission lines, a mixture of 500kV and 161kV lines. Those lines provided power from TVA to 128 regional distributors.

Transmission tower bent near Huntsville, Alabama.

TVA lost the ability to transmit power from both Browns Ferry Nuclear Power Plant and Widows Creek Fossil Plant after the storms on April 27, requiring both to be shut down. The nuclear plant's cold shutdown was supported by diesel generators for four days until a second 161kV line could be restored to the plant. The loss of redundant off-site power required a "notification of unusual event", the lowest of four levels of concern dictated by the NRC. Some 60 percent of the sirens for warning residents of worse problems around Browns Ferry were disabled by the storms, and the plant had to arrange plans to use cars with loudspeakers to warn residents in case of another problem. The Nuclear Regulatory Commission stated at a press conference: "The plants' conditions are stable and are being placed in a cooled-down condition."

Huntsville was the largest city with no electricity from TVA. All the traffic lights were off, a dusk-to-dawn curfew was imposed, students were sent home from United States Space Camp, and the Panoply Arts Festival was canceled. Power was restored gradually to Huntsville, beginning with 3 percent on the morning of May 1. Only localized outages remained eight days after the storm. In addition to traffic and safety issues, the outage caused difficulties with water treatment and distribution and retail of all kinds, including gasoline and food purchases.

Ontario electricity outages were minor, mostly caused by the windstorms of April 28. Although they affected thousands of people at different times throughout the day, all power was restored by the end of the day.

See also

• List of North American tornadoes and tornado outbreaks
• List of F5 and EF5 tornadoes
• Tornadoes of 2011
• List of disasters in the United States by death toll
• Tornado records
• Tri-State Tornado – Deadliest tornado in North America, and made March 18, 1925 the deadliest tornado day recorded in United States.
• 1932 Deep South tornado outbreak – Deadliest tornado outbreak in Alabama history, including an F4 tornado that tracked through Tuscaloosa.
• 1936 Tupelo–Gainesville tornado outbreak – Infamous tornado outbreak occurring on April 5–6, 1936. Deadliest U.S. tornado outbreak since the March 1925 (Tri-State Tornado) outbreak, thus surpassing the March 1932, April 1974, and April 2011 outbreaks in total fatalities.
• April 1956 Birmingham tornado – F4 tornado that hit the northern Birmingham suburbs on April 15, 1956.
• 1974 Super Outbreak – Infamous tornado outbreak occurring on April 3–4, 1974, similar in severity to the 2011 Super Outbreak; though the 2011 event surpassed the 1974 Super Outbreak as the largest recorded outbreak.
• April 1977 Birmingham tornado – F5 tornado that hit the northern Birmingham suburbs on April 4, 1977.
• 1994 Palm Sunday tornado outbreak – March 27, 1994 outbreak that produced an F4 tornado in St. Clair, Calhoun and Cherokee Counties in north-central Alabama.
• April 1998 Birmingham tornado – F5 tornado that struck western parts of Birmingham on April 8, 1998.
• December 2000 Tuscaloosa tornado – F4 tornado that hit southeast suburbs of Tuscaloosa on December 16, 2000.

2009 Pacific Northwest heat wave derecho series

2009 Pacific Northwest heat wave derecho series

Composite radar image as the storm moved from Indiana to Virginia
Date(s)	July 27–August 3, 2009
Duration	~18 hours (10:00 AM-4:00 AM)
Peak wind gust  (measured)	64 mph (103 km/h; 28.6 m/s) (Moscow, Idaho)
Largest hail	2.25 in (5.7 cm) (Deschutes County, Oregon)
Tornado count	None confirmed
Fatalities	25 total
Damage costs	$760 million in the U.S., $234 million CAD in Canada
Areas affected	Washington, Oregon, Idaho, and coastal southwestern British Columbia

The June 2012 Mid-Atlantic and Midwest derecho was one of the most destructive and deadly fast-moving severe thunderstorm complexes in North American history. The progressive derecho tracked across a large section of the Midwestern United States and across the central Appalachians into the mid-Atlantic states on the afternoon and evening of June 29, 2012, and into the early morning of June 30, 2012. It resulted in a total of 22 deaths, millions of power outages across the entire affected region, and a damage total of US $2.9 billion which exceeded that of all but the top 25 Atlantic tropical cyclones. The storm prompted the issuance of four separate severe thunderstorm watches by the Storm Prediction Center. A second storm in the late afternoon caused another watch to be issued across Iowa and Illinois.