Scientists measure tornadoes by wind speed and the devastation that wind leaves behind. They are rated EF-0 to EF-5 on the Enhanced Fugita (EF) Tornado Damage Scale. Most tornadoes are rated below EF-2.
No tornado probe thrust into the path of a "twister" has survived to measure wind speed. TOTO nearly succeeded in the 1980s, as did VORTEX. VORTEX2 just finished its project in June 2010.
VORTEX 2 collected data by using 38 deployable instruments to measure wind speeds. Sticknets, tornado-pods, disdrometers, unmanned aircraft and weather balloons headed an arsenal of teams with Doppler radars. Data continues to be assessed as of November 2010.
Until scientists can create probes that withstand horrific tornado wind speeds, meteorologists will continue to use Doppler radar to estimate wind speed and damage assessments to estimate tornado strength. Scientists hope to increase tornado warning lead time from 13 minutes to 20 minutes or more, perhaps averting wiping homes and lives off the map.