Five people were killed in the town of Greenfield, Iowa and dozens more were left injured following a significant tornado outbreak in the Midwest on Tuesday – and scientists are sifting through metaphorical tons of data following several close-range intercepts by chaser teams and mobile doppler radars alike to try and discern features yet unseen in the lowest levels of tornadoes that may help improve forecasts in the years and decades to come.
For much of the Spring tornado season to date, the Doppler on Wheels teams have been in hot pursuit of tornadic supercells, having throughout the year already intercepted several tornadoes across several states as part of the National Science Foundation-sponsored BEST (Boundary-layer Evolution and Structure of Tornadoes) project, which aims to measure wind speeds using radar and probes placed in the path in the lowest 250ft of tornadoes, which is thought to harbor the highest winds within a tornado vortex – and, of course, is the region of tornadoes that directly impacts our communities and livelihoods here on the ground.
On Tuesday, Doppler on Wheels 6 and 7 were positioned near Greenfield, Iowa, when a violent tornado touched down Southwest of town. As the tornado moved closer to the town itself, it also inched within range of both radars, providing near-record breaking data within the lowest portion of the vortex. On Doppler on Wheels 6, winds were observed at nearly 215mph, and it’s sibling Doppler on Wheels 7 measured winds of ~250mph in the city of Greenfield, with some estimates placing the true maximum in the range of up to 290mph. If this turns out to be true following further analysis and quality control measures, this would place it within the top 5 highest wind speeds ever measured – only being beaten by the likes of the Moore tornado of 1999, and the El Reno tornado of 2013, both of which were near or exceeded 300mph in measured windspeeds. The tornado has been assigned a preliminary rating of “EF-3+”, with more updates to follow in the coming days.
