June 2<< back
by Hummer Storm Chaser
Monster in the Sky
Sitting in the 40 or so minivans, trucks, cars, and the H3T in a parking lot in Kimball, Nebraska, Friday at 4 pm, the VORTEX2 project was waiting for a call to go mobile by the Field Coordinators in an ambulance-sized mobile office. Eric Rassmussen and David Dowell had been constantly studying weather forecasting models and radar and weather balloon data for hours, and had made their best guesses at where the team was most likely to intercept a tornado.
A supercell storm was gathering energy above La Grange, Wyoming, maybe an hour from the waiting chasers, and the teams deployed. Once the vehicles got closer, they disbursed to locations radioed by their team leaders, and the H3T followed the CSWR Doppler On Wheels radar truck number 7 to highway 85 in Wyoming, among rolling hills and bluffs and a few non-descript missile silo sites on the side of the pavement.
As the supercell grew, a classic dark wall cloud hung over the plains, producing a funnel cloud, which gently dropped to the ground. The storm was remarkably silent, while the H3T began its mission of placing instrument pods on the side of the road in 150-meter spacing. Three other probe vehicles from CSWR also dropped pods, making a total of 12 in the path of the tornado. Sean Casey’s Tornado Intercept Vehicle and the National Severe Storms Laboratory’s seven probe minivans also began transecting highway 85 as the tornado approached.
“Who knew this nice confined cell would become a roaring MCS [mesoscale convective system] and chase us all the way back to Kearney,” said Friday’s lead scientist Don Burgess. “We were truly able to find the needle in the haystack.”
The tornado crossed highway 85 in about 15 minutes, reaching speeds of 125 mph measured on the TIV, which was rocked and shaken as it sat filming the twister from ground zero. The storm also dropped hail up to four inches, smashing the windshields of two of the NSSL vans, and demolishing the instruments on the top of the TIV.
Electric poles snapped off at their bases, an unusual place to break, and were held from being dragged along the ground by the wind only by their wires. The pods dropped by the CSWR probes and H3T probe remained intact, and survived the hit gathering data along with the other VORTEX2 teams that has rarely been as extensive.
Officially described as a truncated cone, the tornado was filmed and broadcast live by The Weather Channel, a first for a national broadcast, as well as a live webcast. For another 20 minutes the tornado transformed into a brightly lit tube that whisked under its supercell before finally rising back into the storm.
This supercell, which originated in Chugwater, Wyoming, moved east into Nebraska, looming darkly over Dalton, Nebraska, while the H3T chased it into the plains. As the supercell diminished, a neighboring cell grew, dropping the second tornado reported in the U.S. Friday in Paxton, Nebraska, about an hour east. For the next few hours this cell also pummeled Interstate 80 with hail into the night, forcing the westbound lanes to close. Finally, very late at night, it dropped 2.5 inches of rain on Omaha, perhaps 400 miles from where the storm systems originally began.