TWISTEX Field Operations for April 28, 2011

April 28, 2011 – 6:45 am

Currently in a southern suburb of Birmingham, AL


Historic tornado outbreak in Dixie Alley yesterday with a reported 162 tornadoes (as of SPC this morning).  All of the severe weather parameters were textbook perfect, with sickle-shaped hodographs everywhere in Mississippi and Alabama, and with incredible low level shear, provided the perfect environment for destructive tornadoes. Almost every storm that initiated in Dixie Ally created tornadoes sometime during their lifespan.

Intercepted numerous violent tornadoes including the long-track tornado that moved through the Tuscaloosa and Birmingham area claiming numerous lives.  These tornadoes were moving at 50 MPH making any kind of instrument deployment extremely dangerous.  We witnessed the Tuscaloosa tornado about 30 miles to the southwest of Tuscaloosa, and immediately called emergency personnel warning them of the tornado in progress.

All of these tornadoes were only intercepted once as they passed the highway in front of the team.  One interesting item of note–these tornadoes were passing through trees that were 40-80′ high, and noted that due to the surface roughness(created by the trees themselves), the tornado vortex was very disorganized near the ground, and by visual observations-the collective wind speed was considerably less.   Even these violent tornadoes were not simply a ‘buzz saw’ moving through the trees maintaining good vortex structure.  As the vortex crossed the road in front of us, it briefly ‘organized’ into a continuous ‘cone’, then broke apart as it progressed to the east back into the vegetation.

Kudos to the entire team yesterday.


Today begins a multiple drive day back to Colorado.  There is a small opportunity for a chase in SE OK on Saturday, but this will be carefully monitored and weighted on delegating time to fully prepare for full TWISTEX operations in a week.

RADAR installation will likely commence sometime next week if all the hardware is ready.


After a brief return of severe weather in OK on Saturday, we might get a long needed break for the crew to continue final preparations.

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