The Elusive Snow Tornado

Mar 5, 2012; 8:00 AM ET

We’re seeing something rare, but not unprecedented this morning: snow on tornado damage. Here’s an image from Twitter this morning via my Facebook friend Chickage Windler, a meteorologist for WTHR:

It’s not terribly unusual for spring storms to bring snow after tornadoes, but this much snow on top of this much damage is extremely rare – I personally have never seen it.

But has a tornado every happened to an already-snow-covered area? My friend meteorologist Paul Douglas had some excellent observations pointed out this television screen capture forwarded to him by a friend may show a tornado over snow cover:

He said on Twitter: “Never seen this before: Nebraska tornado with patches of snow still on the ground? Highly unusual.” I would agree. The elusive “snow tornado” (even more elusive than a purple squirrel) has been rumored by many but proven by no one. It’s a meteorologically tricky situation that wouldn’t normally occur. You’d need snow before the tornado that didn’t get melted by the approaching warm air associated with the twister, or melted by its rain. It’s much more often to have snow after a tornado, when the cold front passes and temperatures fall.

This capture, which came from Mike Umscheid Photography’s Facebook Page does look like snow at first glance, and another video appears to show something similar. The tornado was in Stapleton, central Nebraska.

What weather data can we use to confirm this? According to AccuWeather.com, weather data from the nearest airport (North Platte, 20 mi. SW) indicated that there had been “zero” snow cover for the last 11 days, though they did report a trace of snow on Feb. 20th. Given high temperatures in the 50s since then, it should all be gone. A map from NOAA NOHRSC says that there was no little snow cover near Stapleton yesterday, but this is only a satellite estimate.

If it’s not snow, what is it? It could be standing water from the storm, reflecting the bright sky above the twister, or it could be ice (lows at North Platte have been below freezing for the last ten days). I have an email out to Mike, who should know the answer, and I’ll post here when he replies.