Two-day U.S. Tornado Outbreak Kills at Least 29 People; More Tornadoes Expected Today

A swarm of deadly and devastating tornadoes ripped through the Southeast U.S. on Monday, killing at least 13 people, bringing the two-day death toll from this week’s tornado outbreak to at least 29. Hardest hit were Mississippi and Alabama, which lay in the bullseye of the High Risk” area for severe weather issued by NOAA’s Storm Prediction Center early that afternoon. It was the second consecutive day a “High Risk” outlook had been issued by SPC, and the threat of strong and deadly tornadoes continues again on Tuesday, with a “Moderate Risk” of severe weather expected over Alabama and Mississippi. The tornado activity in Mississippi and Alabama on Monday was remarkably violent and long-lasting; Alabama’s first tornado warning was issued at 12:37 pm CDT, and the last was nearly sixteen hours later, at 4:20 am (thanks to wunderground member sar2401 in Alabama for this info.) Mississippi suffered the highest death toll on Monday, with eight killed. Three people died in Alabama, including a University of Alabama swimmer who died saving his girlfriend from a collapsing building. Two other people died in Lincoln County, Tennessee, near the border with Alabama. In all, for the 24-hour period beginning at 8 am Monday, SPC logged 64 preliminary tornado reports from five states, along with 135 reports of damaging winds and 49 reports of hail. An additional 33 preliminary tornado reports came on Sunday, bringing the two-day preliminary tornado total to 97. Hardest hit on Sunday was Arkansas, where fifteen people died in tornadoes. Mayflower and Vilonia, Arkansas, located about fifteen miles northwest and north of Little Rock, had ten people killed by a tornado that has been preliminarily rated as at least an EF-3 by the National Weather Service. Sunday tornadoes also killed one person in Iowa and one in Oklahoma.


Figure 1. Tornado damage in Tupelo, Mississippi, pictured Monday evening. (J. Robert Senseman)


Figure 2. Radar reflectivity image of the supercell thunderstorm that hit Tupelo, Mississippi at 19:39 UTC (3:39 pm EDT) on April 28, 2014. Tupelo’s position is denoted by the circle with a “+“ in it, and lies next to a hook-shaped echo commonly seen in strong tornadoes. The Tupelo tornado killed one person in a car, and was preliminarily rated an EF-2 with winds of 111 - 135 mph. Radar data showed that this tornado lofted debris 35,000 feet into the air.


Figure 3. Doppler velocity image of the supercell thunderstorm that hit Tupelo, Mississippi. Note the clump of green colors lying right next to orange and red colors near Tupelo, showing that winds moving both towards the radar and away from the radar were located in close proximity to each other—the signature of a rotating mesocyclone in a severe thunderstorm capable of spawning a strong tornado.


Figure 4. Severe weather outlook for Tuesday, April 29, 2014, as issued on Tueday by NOAA's Storm Prediction Center.

Tornado and severe weather outbreak continues on Tuesday and Wednesday
The strong, slow-moving low pressure system that brought this weekend’s deadly tornadoes will spawn spawn more supercell thunderstorms capable of generating large hail, damaging winds, and a few strong tornadoes on Tuesday. NOAA's Storm Prediction Center (SPC) has issued their "Moderate Risk" forecast of severe weather over much of Mississippi and Alabama for Tuesday, with a wide swath of the Eastern half of the U.S. under a “Slight Risk” of severe weather. The set-up for getting strong tornadoes does not appear to be as dangerous today as it was on Monday, and I don’t think we will see as many tornadoes. The upper-level winds over the Southeast U.S. will not be as strong, leading to less wind shear available to get tornadoes spinning. Still, instability will be very high, and I do expect we will see a few strong EF-3 tornadoes in Mississippi and Alabama. The risk of severe weather will diminish considerably on Wednesday, but most of the Southeast U.S. will be still be in SPC’s “Slight Risk” region for severe weather. The severe threat will finally end Thursday morning as the cold front responsible moves off the coast.


Video 1. This animation of NOAA's GOES-East satellite data shows the development and movement of the weather system that spawned tornadoes affecting seven central and southern U.S. states on April 27-28, 2014. Credit: NASA/NOAA GOES Project


Video 2. Scott Peake's close-up intercept of the strong-violent Louisville, MS tornado on April 28, 2014.

New Wunderground Tornado Infographics
Weather Underground has just released two new tornado infographics. Share these with your friends living in at-risk areas for tornadoes:

Tornadoes Cities and Interstates: http://www.wunderground.com/weather-infographics/tornadoes/

Tornado Safety: http://www.wunderground.com/weather-infographics/tornado-safety/



In the tornado safety infographic, we recommend driving away from a tornado rather than parking your vehicle beneath a freeway overpass. Keep in mind that a vehicle is one of the worst places you can be in a tornado, as the tornado's winds can easily roll a car. (The only place less safe is probably a mobile home, as a tornado's winds can roll mobile homes almost as readily, and mobile homes don't come with seat belts and air bags.) If you are located in a metro area and don't have an underground shelter, the best thing to do it to take shelter in an interior windowless room or hallway, with protective furniture over your body. Getting in a car and attempting to flee the tornado is the worst thing you can do in an urban area. You may not be able to see the tornado if it is dark or the tornado is wrapped in rain. You are likely to encounter hazardous winds, rain, and hail, run into unexpected traffic, or flooded or debris-blocked roads that will put you directly in the path of the tornado. Even without an underground shelter, most people will be able to survive a dangerous EF-4 tornado. Sometimes it is better to abandon your vehicle and take shelter in a ditch, if you are caught in a car during a tornado. However, if there is already flying debris in the air, leaving your car and exposing yourself to the debris in order to get to a ditch may be more hazardous than staying in your car. Furthermore, ditches are prone to flash floods. A 2002 research paper, "UNSAFE AT ANY (WIND) SPEED? Testing the Stability of Motor Vehicles in Severe Winds" found that: "The stability and superior safety of being in a vehicle in severe winds, relative to occupying a mobile home or being outdoors, should be considered." Also, TWC's severe weather expert, Dr. Greg Forbes, commented on the pros and cons of abandoning one's vehicle for a ditch in a 2009 blog post, "Tornado Safety - Cars Versus Ditches: A Controversy." His personal take on what he would do if his car was being overtaken by a tornado, and no sturdy buildings were nearby to take shelter in: "I can't see myself getting out of the vehicle. I'd try first to drive away from the tornado. Both the NWS and the American Red Cross actually also advocate this. If you can determine which way the tornado is moving toward, face your body toward that direction and then go to the right. That is usually toward the south or southeast. The reason that it's best to head this way is that if you went to the left you would normally get into the region where largest hail and blinding rain occur in the kind of supercell, rotating thunderstorms that often spawn tornadoes. If I had no such driving option and I did feel the urge to get out of my car, I'd try to get into a building, and into a ditch well away from the car as the last resort."

Disaster Relief Donations Needed
The devastation from this week’s tornadoes have brought a need for donations for disaster relief. The Portlight.org disaster relief charity, founded by members of the wunderground community, is supporting the efforts of a group of local volunteers in Arkansas doing search and rescue, and needs donations. Portlight volunteers are working in tornado-hit towns to clear debris and help with other clean-up efforts. This team will also be visiting shelters and reaching out to survivors with disabilities to determine their immediate needs, whether for replacement of durable medical equipment and ramps, or for assistance with shelter and transportation issues. The Red Cross is also a great place to send your donation dollars.

Jeff Masters