More than 1,200 tornadoes rip through the U.S. Midwest in an average year, killing about 100 people and costing millions of dollars in damage. Currently the longest warning time meteorologists can give is a nerve-racking 13 minutes, with a 70 percent false alarm rate.

Scientists aim to improve this. On May 1, an armada of more than 100 scientists driving 40 trucks will cross the Great Plains on the hunt for twisters. The two-year project called VORTEX2 is the largest field experiment in history. With more than $10 million in funding from the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA), researchers from more than a dozen universities and several government and private organizations hope to learn more about the formation, structure and evolution of tornadoes.

Scientific American caught up with VORTEX2 in the field last May. In this exclusive video we find out what scientists still don't know but could soon figure out about one of nature's most violent and unpredictable forces.

7 Comments

1. 1. jtdwyer 02:37 PM 4/30/10

   The critical factor in the development of vertical vortices is the temperature differential between high temperature surface level air and swiftly moving cooler air at higher altitudes. If cold air ever overlays warm air (and ground or water), vortices develop. I have not studied this in the laboratory, but I did grow up in Texas, Oklahoma and Kansas 60 years ago. I don't understand why none of the scientists in the video didn't mention it.
   
   The criticality of the temperature differential, as opposed to just high water temperature, means that the conventional wisdom stating that global warming will increase the incidence and intensity of hurricanes may be incorrect.

   Reply | Report Abuse | Link to this

2. 2. billsmith in reply to stew6302 11:31 PM 4/30/10

   @stew6302
   Oh? Can you name a few similar weather research projects that failed to produce benefits?

   Reply | Report Abuse | Link to this

3. 3. wolfkiss 04:15 AM 5/1/10

   I could imagine jtdwyer's observation being like a rip tide on the sea shore. There would be a cold layer over a warm layer. The cold wants to come down and the warm wants to go up. Like a sandbar breaking to make a rip tide, a hole could form in a thin spot in the cold layer. Following the path of least resistance, the cold air goes down and the warm air goes up in this "two way drain". The cold and the warm spin down/up this drain relieving the pressure differential, spinning around each other in a cumulative manner; each reinforcing the others angular momentum.
   
   Refining this speculation...perhaps the warm punches a hole through the cold layer and then the cold fills the less dense volume of ascending warm air beneath, thus making its own way down to the ground. This would be consistent with the observation that tornadoes/twisters typically start the funnel up off the ground, because the warm air breaks through the cold layer to some less dense layer even higher. Later, the cold follows the escaping warm air down to the ground to "touch down". It would be one drain connecting with another winding past each other in the exchange. The faster the column of air spins the tighter it gets, like the ice skater analogy.
   
   So, if I had $10mill to study this, I'd try to find indicators for general areas with a large temperature differential. Once in this general area, I'd try to find a localized "dimple" in the cold layer; i.e. an area where the cold layer is thinner with a warm layer on top of it...just a thought.

   Reply | Report Abuse | Link to this

4. 4. jtdwyer 06:00 AM 5/1/10

   wolfkiss - The tornado warning sirens just woke me up: looks like it's at least premature for my location in the Eastern part of the county...
   
   Re. you comment, I favor your warm air rising scenario for tornadoes. Generally this configuration of air-temperature layers most often occurs when, after a warm, humid day, a cold front blows in from the west, carrying moist, cooler air. The result is general turbulent conditions favoring the formation of tornadoes.
   
   Classically, the warmer air is unusually calm as the cold air approaches, and one can sometimes actually feel the barometric pressure drop. As one lady said on the video, if the sky turns greenish in color (during the day of course), think about taking cover.
   
   Looking at the radar, the rain should break the sudden calm soon: I'm thinking about going back to sleep.

   Reply | Report Abuse | Link to this

5. 5. 1bobwhite 09:55 AM 5/1/10

   When I was in Aurora Colorado in the seventies, on one memorable weather day I watched through my binoculars five tornadoes and three funnel clouds at the same moment out on the plains toward Kansas, and of course no camera. The squall line had just past so I was in clear air to observe this. Yesterday here in Missouri we dodged yet again another series of tornadoes. Maybe the research teams should come here and just wait for the tornadoes to come to them, it wont take long.

   Reply | Report Abuse | Link to this

6. 6. jack.123 07:21 AM 5/4/10

   One of the things missing in the study of tornadoes is the electromagnetic aspect of these objects,and it might explain why one storm will produce a tornado,and another storm apparently the same doesn't.

   Reply | Report Abuse | Link to this

7. 7. sankravelayudhan nandakumar 07:52 PM 8/7/10

   Solar rays could be converged to produce cross polarized Bossonova resonance between Air affined and water affined middle frequency resonance as Monster twisters in ferromagnetic cloud chambers for tapping energy Electricity
   An interesting Cross Polarized Bossoneva Twisters(CPBT) convergence in laser cooling dynamics that oscillate between air affined surface polaritons forming cross polarized as they oscillate along middle frequencies in fferro magnetic vaporized cloud chambers of MOT requires further research in NIST,and Jila ,MIT University.

   Reply | Report Abuse | Link to this