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Tornado Tally
During its two field seasons (April 1-June 15, 1994 & 1995), VORTEX scientists intercepted ten individual tornadoes:
A weak tornado with an erratic path that crossed west of Corrum, Okla., near Waurika Lake on April 17, 1994. This storm continued to produce tornadoes and mesocyclones (a rotating column of rising air that often produces tornadoes) for a number of hours as it moved through southeastern Oklahoma.
A weak tornado near Kaw Reservoir, Okla., on May 6, 1994. This storm produced much more wind damage than tornado damage.
A strong tornado near Northfield, Tex., on May 25, 1994.
A violent tornado near Newcastle, Tex., on May 29, 1994. This tornado went virtually undetected by radar, while a nearby mesocyclone, which was well detected, did not produce a tornado.
A weak tornado near Hays, Kansas, on May 12, 1995, from a storm that produced softball-sized hail. This giant supercell (steady- state thunderstorm) may help explain why only weak tornadoes or no tornadoes form from storms that are expected to generate significant tornadic activity.
A strong tornado southwest of Hanston, Kansas, on May 16, 1995, that followed a large tornado that formed near Garden City before the VORTEX armada arrived. The Hanston tornado intensified and grew in size, remaining on the ground for at least 30 minutes as it moved over open country south of Burdett and Rozel. VORTEX obtained excellent mobile scanning Doppler data of this tornado, video from numerous angles, and very comprehensive and wide- ranging meteorological data from one intercept team that managed to stay ahead of the tornado. The NOAA P-3 aircraft collected data throughout the tornadic phase of the storm. The mesocyclone that spawned the tornado moved directly over the VORTEX armada as it moved into open country.
Two violent tornadoes near Friona and Dimmitt, Texas, on June 2, 1995. The Friona tornado caused over $12 million in damage at one feed mill alone, knocked a freight train off its tracks, destroyed an airport, and was strong enough to bounce a railroad boxcar over 100 meters. At one point, there were two large tornadoes rotating around each other. The Dimmitt tornado was strong enough to rip up highway pavement, and carried automobiles hundreds of meters before destroying them. The Dimmitt tornado was the most thoroughly observed tornado in history, closely followed by VORTEX researchers from beginning to end.
Two violent tornadoes near Kellerville and Allison, Texas, on June 8, 1995. The large tornado that formed south of Kellerville, probably an F5, ripped up highway pavement and was on the ground for over an hour, covering nearly 30 miles. A second tornado developed about six miles southwest of Allison, moved directly toward Allison, then veered to the left, passing within 1.5 miles west of the town. It was one of the largest tornadoes ever observed, with F3 damage extending over a one-mile swath. Mobile scanning Doppler and the WSR-88D radar depicted as many as four tornadoes and/or mesocyclones that occurred simultaneously within a 12-mile-square area north of the Briscoe/Allison Road. The Allison tornado was so large that it was difficult for even trained tornado spotters to identify it as a tornado.
The Observations
On almost every storm, VORTEX scientists collected continuous airborne Doppler data to compute winds throughout the updraft, mesocyclone, and tornado region of the storm.
In 1995, the NOAA P-3 and NCAR Electra storm reconnaissance aircraft took complete "pictures" of winds approximately every five minutes. In 1994, the NOAA P-3 only took part in the experiment. These new wind data sets are several times more comprehensive in the number of data points and frequency of collection than for any storm studied previously.
Many thousands of individual weather observations (temperature, humidity, barometric pressure, wind speed and direction) were collected by 16 vehicles in each storm, with each vehicle's position plotted precisely using the Global Positioning System. This is thousands of times more surface data than have ever been collected near a supercell storm.
From three to eight weather balloons were launched into most storms and another three to eight balloons were launched near the storms, transmitting a nearly continuous stream of meteorological information from the ground up during the observed storm. One of these balloons revealed air in one thunderstorm updraft rising at 60 meters per second (about 135 mph). The balloon data are many times more comprehensive than ever collected in and near supercell storms.
Each storm was photographed and videotaped from several angles. The Dimmitt, Texas, tornado was videotaped from several distinct angles at fairly close range (within five kilometers).
First deployed in mid-May 1995, a one-of-a-kind truck- mounted research radar documented in unprecedented detail wind speeds and reflectivity in the May 16 Hanston, Kansas, tornado from a distance of only about six kilometers. This "weather radar on wheels," developed by VORTEX researchers, also collected data from the violent June 2 Dimmitt tornado from about three km from the tornado, clearly showing the tornado itself, including the debris cloud and hollow core. This radar also probed several significant tornadoes at close range in June. Because the radar scans the entire mesocyclone region (the region of the storm that contains the rotating air) every 90 seconds, these radar data should provide major clues into how tornadoes form and persist.