Tornadoes and huge hail pound the Plains

A barrage of 65 tornadoes ripped through Texas, Oklahoma, Kansas, Colorado, and Nebraska last night. Two people were killed in the Oklahoma Panhandle when a tornado destroyed their house. Tornadoes also killed one person in Colorado, and one person in Texas. Several of the tornadoes were large, long-lived, and possibly violent EF4 twisters. Since the Enhanced Fujita rating scale is a damage scale, we may never know how strong some of these tornadoes were, as they mostly missed populated areas where they could do damage.

One supercell thunderstorm in the Texas Panhandle spawned a tornado that hit a rest area along I-40, flipping 18-wheelers parked there. This storm may have done enough damage to get an EF-scale rating. The thunderstorm also produced 4.5 inch diameter hail (softball sized!), which one doesn't see very often anywhere in the world. Looking at the radar reflectivity from this storm (Figure 1), we see that the echoes from this storm were near the top of the scale--70 dBZ--thanks in part to these highly reflective large hailstones. Seeing 70 dDZ on the radar is another rarity!


Figure 1. Radar reflectivity image of the March 28, 2007 thunderstorm that produced a tornado and softball-sized hail as it crossed I-40 east of Amarillo, Texas.

We got lucky with last night's storms, which all missed populated areas. What would happen if we got unlucky? What would a violent EF5 tornado do to Chicago or some other densely populated urban area? That was the cover story of January's issue of the Bulletin of the American Meteorological Society, which I'll discuss tomorrow.

Jeff Masters