Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 1:50 PM GMT on May 24, 2011
Severe weather is expected again today in storm-torn Joplin, Missouri, as rescuers sift through the rubble of their town that was devastated by the deadliest U.S. tornado since at least 1947. A violent high-end EF-4 tornado with winds of 190 – 198 mph carved a 7-mile long, ¾ to one mile-wide path of near-total destruction through Joplin beginning at 5:41pm CDT Sunday evening. In nine terrifying minutes, the tornado killed at least 116 people, injured 500 more, and obliterated huge sections of the town. Damage from the tornado is so severe that pavement was ripped from the ground, and the level of damage is so extreme that this is likely to surpass last month's Tuscaloosa-Birmingham tornado as the costliest tornado of all-time.
Figure 1. Radar reflectivity image of the supercell thunderstorm that spawned the Joplin, Missouri tornado, one minute before the tornado touched down at 5:41pm CDT. There is a hook echo apparent, though not a classic well-defined one.
Figure 2. Radar-estimated rainfall for the period May 22 – 24 over the region surrounding Joplin. Rains of 1.83" fell on the city yesterday, a record for the date.
The Joplin tornado's place in history
According to our weather historian, Christopher C. Burt in his post, The World's Deadliest Tornadoes, the death toll of 116 from the Joplin tornado ranks as the deadliest U.S. tornado since at least 1947, when a violent F-5 tornado hit Woodward, Oklahoma, killing 181. However, it is now thought that the Woodward tornado was actually one of a series of tornadoes, and the tornado that hit Woodward killed 107 people. If that is true, we have to back all the way to 1936 to find the last U.S. tornado that killed more people than 2011's Joplin tornado. In 1936, violent tornadoes a day apart hit Tupelo Mississippi (216 killed), and Gainesville, Georgia (203 killed.) NOAA's Storm Prediction Center (SPC) rates this year's Joplin tornado as the 9th deadliest U.S. tornado of all-time.
This year's tornado death toll now stands at 482, making it the deadliest year for tornadoes in the U.S. since 1953, when 519 people died. That year, three heavily populated cities received direct hits by violent tornadoes. Waco, Texas (114 killed), Flint, Michigan (115 killed), and Worcester, Massachusetts (89 – 94 killed) all were hit by violent F-4 or F-5 tornadoes. A similar bad tornado year occurred in 1936, when violent tornadoes hit Tupelo Mississippi (216 killed), and Gainesville, Georgia (203 killed.)
Video 1. The last year with more tornado deaths than 2011 was 1953, when three great tornadoes killed more than 90 people each. This old newsreel video shows destruction from the first of these deadly 1953 tornadoes, the May 11, 1953 F-5 tornado that hit downtown Waco Texas, killing 114 people. The wunderground youtube channel has almost 300 old newsreel videos of historically significant weather events.
What's going on?
It's been an incredibly dangerous and deadly year for tornadoes. On April 14 - 16, we had the largest tornado outbreak in world history, with 162 tornadoes hitting the Southeast U.S. That record lasted just two weeks, when the unbelievable April 25 – 28 Super Outbreak hit. Unofficially, that outbreak had 327 tornadoes, more than double the previous record. The legendary April 3 – 4 1974 Super Outbreak has now fallen to third place, with 148 tornadoes. Damage from the April 25 – 28, 2011 outbreak was estimated to be as high as $5 billion, making it the most expensive tornado outbreak in history; the Tuscaloosa-Birmingham tornado of April 27 may end up being the most expensive tornado of all-time—until the damage from Sunday's Joplin tornado is tabulated. Officially, 875 tornadoes hit the U.S. In April 2011, making it the busiest tornado month in history. The previous record was 542 tornadoes, set in May 2003. The previous April tornado record was 267, set in 1974, and April has averaged just 161 tornadoes over the past decade.
So what's going on? Why are there so many tornadoes, and so many people getting killed? Well, the high death toll this year is partly just bad luck. Violent EF-4 and EF-5 tornadoes usually miss heavily populated areas, and we've had the misfortune of having two such tornadoes track over cities with more than 50,000 people (the Joplin tornado, and the Tuscaloosa-Birmingham EF-4 tornado in Alabama, which killed 61 people on April 27.) This sort of bad luck occurred in both 1953, when F-5 tornadoes hit Flint, Worcester, and Waco, and in 1936, when F-5s hit Tupelo and Gainesville. However, this year's death toll is more remarkable than the 1953 or 1936 death tolls, since in 2011 we have Doppler radar and a modern tornado warning system that is very good at providing an average of twelve minutes of warning time. The warning time for the Joplin tornado was 24 minutes. The first tornado warning wasn't issued until 1948, and virtually all tornadoes from the 1950s and earlier hit with no warning. On average, tornado deaths in the United States decreased from 8 per 1 million people in 1925 to 0.12 per 1 million people in 2000. Had this year's tornadoes occurred 50 years ago, I expect the death toll would have exceeded three thousand.
Figure 3. Number of strong to violent EF-3, EF-4 and EF-5 tornadoes from 1950 to 2011. There are no obvious trends in the numbers of these most dangerous of tornadoes. Image credit: NOAA/National Climatic Data Center (updated using stats for 2008 – 2011 from Wikipedia.)
Tornadoes require two main ingredients for formation—instability and wind shear. Instability is at a maximum when there is record warm air with plenty of moisture at low levels, and cold dry air aloft. April 2011 sea surface temperature in the Gulf of Mexico were at their third highest levels of the past 100 years, so there was plenty of warm, moist air available to create high instability, whenever approaching storm systems pulled the Gulf air northwards into Tornado Alley, and brought cold, dry air south from Canada. The La Niña event in the Eastern Pacific, in part, caused this spring's jet stream to have very strong winds that changed speed and direction with height. This sort of shearing force (wind shear) was ideal for putting a twist on thunderstorm updrafts, allowing more numerous and more intense tornadoes than usual to occur. Was this year's heightened wind shear and instability the result of climate change? We don't know. Over the past 30 years, there have not been any noticeable trends wind shear and instability over the Lower Mississippi Valley, according to the NOAA Climate Scene Investigations team. Furthermore, there have been no upward trend in the number of violent EF-4 and EF-5 tornadoes over the past 60 years, or in the number of EF-3 and stronger tornadoes (Figure 3.) However, this year's remarkable violent tornado activity—17 such tornadoes, with tornado season a little more than half over—brings our two-year total for the decade of 2010 – 2019 to 30. At this rate, we'll have more than 150 violent tornadoes by decade's end, beating the record of 108 set in the 1950s. In summary, this year's incredibly violent tornado season is not part of a trend. It is either a fluke, the start of a new trend, or an early warning symptom that the climate is growing unstable and is transitioning to a new, higher energy state with the potential to create unprecedented weather and climate events. All are reasonable explanations, but we don't have a long enough history of good tornado data to judge which is most likely to be correct.
More severe weather today
Yesterday, survivors of the tornado endured a 12-hour period with two severe thunderstorm warnings, a record 1.83” of rain, hail, and lightning that struck two police officers. NOAA's Storm Prediction Center (SPC) recorded 11 preliminary reports of tornadoes yesterday, along with 315 reports of damaging winds and 182 reports of hail up to 3.5” in diameter. The severe weather threat is much higher today, and SPC has placed a large section of eastern Kansas and eastern Oklahoma in their "High Risk" region for severe weather potential, and warn of the potential for long-lived strong tornadoes. This is their third "High Risk" forecast for the year, and the first since the terrible April 27, 2011 tornado outbreak. That day was the busiest tornado day in world history, with 198 tornadoes occurring in a 24-hour period. Over 300 people died. The other "High Risk" forecast by SPC came during the final day of the April 14 – 16 outbreak over the Southeast U.S. Fifty-two tornadoes hit that day, and 26 people died in North Carolina and Virginia. The severe weather threat will continue into Wednesday, when additional tornadoes are likely along a swath from Arkansas to Indiana.
Figure 4. Severe weather threat for Tuesday, May 23, 2011.
The most remarkable audio I've ever heard of people surviving a direct hit by a violent tornado was posted to Youtube by someone who took shelter in the walk-in storage refrigerator at a gas station during the Joplin tornado. There isn't much video.
Video 2. Video of the Joplin, Missouri tornado of May 22, 2011, entering the southwest side of town. Filmed by TornadoVideos.net Basehunters team Colt Forney, Isaac Pato, Kevin Rolfs, and Scott Peake.
Helping out tornado victims
For those who want to lend a helping hand to those impacted by the widespread destruction this month's severe weather has brought, stop by the Red Cross website, or portlight.org blog. Portlight has been very active bringing aid to the victims of this year's tornadoes. Below is the damage survey from the Joplin tornado:
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE SPRINGFIELD MO
938 PM CDT MON MAY 23 2011
...JOPLIN TORNADO GIVEN A PRELIMINARY HIGH END EF-4 RATING...
* DATE...22 MAY 2011
* BEGIN LOCATION...APPROXIMATELY 3 MILES SOUTHWEST OF JOPLIN
* END LOCATION...1 MILE SOUTHEAST OF DUQUESNE
* ESTIMATED BEGIN TIME...541 PM
* ESTIMATED END TIME...550 PM
* MAXIMUM EF-SCALE RATING...EF-4
* ESTIMATED MAXIMUM WIND SPEED...190-198 MPH
* ESTIMATED PATH WIDTH...3/4 OF A MILE
* PATH LENGTH...7 MILES
* FATALITIES...116 REPORTED AS OF 3 PM MONDAY
* INJURIES...400 REPORTED AS OF 3 PM MONDAY
* BEGIN LAT/LON...37.06 N / 94.57 W
* END LAT/LON...37.06 N / 94.39 W
NATIONAL WEATHER SERVICE SURVEY TEAMS RATED THE TORNADO THAT KILLED OVER 100 PEOPLE IN AND AROUND JOPLIN AS A HIGH END EF-4 TORNADO.
BASED UPON SURVEYS COMPLETED TODAY...MAXIMUM WINDS WERE ESTIMATED BETWEEN 190 AND 198 MPH. THE TORNADO HAD A MAXIMUM WIDTH OF 3/4 TO ONE MILE.
THE TORNADO INITIALLY TOUCHED DOWN AROUND 541 PM NEAR THE INTERSECTION OF COUNTRY CLUB AND 32ND STREET. ADDITIONAL SURVEYS ARE EXPECTED TO BE CONDUCTED TO FURTHER DEFINE THE STARTING POINT AND INTENSITY AT THIS LOCATION.
DAMAGE BECAME MORE WIDESPREAD AS THE TORNADO CROSSED MAIDEN LANE...CAUSING SIGNIFICANT DAMAGE TO NEARLY ALL WINDOWS ON THREE SIDES OF ST JOHNS HOSPITAL AS WELL AS TO THE ROOF. THE TORNADO FURTHER INTENSIFIED AS IT DESTROYED NUMEROUS HOMES AND BUSINESSES TO THE EAST AND NORTH OF THE HOSPITAL. THE HIGHEST RATED DAMAGE IN THIS AREA WAS TO A CHURCH SCHOOL THAT HAD ALL BUT A PORTION OF ITS EXTERIOR WALLS DESTROYED AS WELL AS TO A NURSING HOME. WINDS IN THAT AREA WERE ESTIMATED AT 160 TO 180 MPH.
THE TORNADO CONTINUED TO DESTROY OVER 100 HOMES BETWEEN 32ND AND 20TH STREETS. THREE STORY APARTMENT COMPLEXES HAD THE TOP TWO FLOORS REMOVED...OTHER TWO STORY COMPLEXES WERE PARTIALLY LEVELED.
A BANK WAS TOTALLY DESTROYED WITH THE EXCEPTION OF THE VAULT.
A DILLONS GROCERY STORE ALSO HAD SIGNIFICANT ROOF AND EXTERIOR WALL DAMAGE. LASTLY...THE EXTERIOR AND INTERIOR WALLS OF A TECHNICAL SCHOOL...A MORTAR AND REBAR REINFORCED CINDER BLOCK BUILDING...FAILED.
THE TORNADO CROSSED RANGELINE ROAD NEAR 20TH STREET. THE MOST INTENSE DAMAGE WAS NOTED JUST EAST OF THIS INTERSECTION WHERE A HOME DEPOT WAS DESTROYED BY AN ESTIMATED 190 TO NEARLY 200 MPH WINDS.
IN ADDITION...THE CUMMINS BUILDING...A CONCRETE BLOCK AND HEAVY STEEL BUILDING...HAD ITS STEEL ROOF BEAMS COLLAPSE. SPORTS ACADEMY AND THE WALMART ALSO SUFFERED SIGNIFICANT DAMAGE.
THE TORNADO CONTINUED TO MOVE EASTWARD ALONG AND SOUTH OF 20TH STREET DESTROYING NUMEROUS WAREHOUSE STYLE FACILITIES AND RESIDENCES THROUGH DUQUESNE ROAD. WINDS IN THIS AREA MAY ALSO APPROACH 200 MPH.
THE TORNADO CONTINUED TO DESTROYING NUMEROUS HOMES BEFORE WEAKENING AS IT TURNED SOUTHEAST TOWARD INTERSTATE 44.
SUBSEQUENT DAMAGE SURVEYS WILL BE REQUIRED TO DETERMINE THE SCOPE OF ADDITIONAL REPORTS ALONG AND SOUTHEAST OF THE INTERSECTION OF HIGHWAY 71 AND INTERSTATE 44.
FOR REFERENCE...THE ENHANCED FUJITA SCALE CLASSIFIES TORNADOES INTO THE FOLLOWING CATEGORIES:
EF0...WIND SPEEDS 65 TO 85 MPH.
EF1...WIND SPEEDS 86 TO 110 MPH.
EF2...WIND SPEEDS 111 TO 135 MPH.
EF3...WIND SPEEDS 136 TO 165 MPH.
EF4...WIND SPEEDS 166 TO 200 MPH.
EF5...WIND SPEEDS GREATER THAN 200 MPH.
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