The National Weather Service’s Storm Prediction Center (SPC) couldn’t have done a better job identifying in advance the Arkansas zone where devastating tornadoes claimed at least 10 lives along a 80-mile path of destruction.  The precision-forecasting and efforts to warn undoubtedly saved many lives, but the gut-wrenching toll proves our best science only goes so far.

(NWS Storm Prediction Center, Greg Carbin)
(NWS Storm Prediction Center, Greg Carbin)

One full day in advance of the massive tornado, SPC’s suite of high resolution forecast models (or “ensemble of opportunity” shown above) pinpointed – with amazing precision – the zone most at risk of rotating storms (see above).  On Sunday morning, SPC declared this zone under a “moderate” or “high” risk of severe thunderstorms and issued timely watches and warnings.

Zones of severe storm risk identified hours (and days) in advance

“Particularly dangerous situation” tornado watch issued in the afternoon

“Tornado emergency” warning issued

But humans only have so many defenses against a half-mile wide vortex of destruction, with textbook radar and satellite presentation:

Pictures and video from Twitter show very wide tornado on the ground

 

Radar imagery shows tight velocity “couplet” where green indicates strong winds blowing towards radar and, immediately adjacent, red indicates strong winds blowing away from it: this signifies very strong rotation in the thunderstorm

Satellite image shows explosive convection or “bubbling” signature, indicative of vigorous vertical motions

Three-dimensional view of storm shows cloud tops extending above 30,000 feet

At least two tornadoes touched down along an 80 mile path

Via the NWS forecast office in Little Rock: An illustration of the path of at least two of the tornadoes that touched down in Arkansas
Via the NWS forecast office in Little Rock: An illustration of the path of at least two of the tornadoes that touched down in Arkansas

The images of the aftermath, especially around Mayflower and Vilonia, are heart-breaking:

When tornadoes this intense strike populated areas, the only safe place may well be underground or in a hardened safe room. Meteorologists continue to work with social scientists to develop strategies that will motivate people to develop and/or seek appropriate shelter in dangerous tornado situations.  Increasingly, tornado predictions are  accurate (the physical science), but our preparedness efforts, involving more social science and the psychology of how people make decisions, are not completely adequate.