Fresh off a light coating of snow just two days ago, visions of what happened May 2nd of last year flashed before us. One year ago tomorrow, every May snow record for SE Minnesota and N Iowa was broken... smashed... destroyed... obliterated! Pick whatever adjective you choose. It doesn't change the fact that the area was smashed with snow that took the area by surprise... even though we were expecting it.
In a blog post immediately after last year's storm on May 2nd I stated before the storm we were expecting record breaking snow. In the forecast was 2-8" of snow for the area. The previous May snow record for Rochester in one day was 2". I was right. We did see record breaking amounts, we just basically doubled what we were expecting.
So what happened? We had a powerful cold front move through the area late on May 1st. Temperatures for the five previous days were in the 70s locally, with the air trailing in the 20s/30s. A narrow but focused band of precipitation huddled around the front and when the colder air hit, we changed to snow. An explosion in snow intensity occured that night with snow rates reaching 2" per hour at times! Despite the talk of warm surroundings melting some snow as it fell (warm ground, wet roads, etc) keeping snow totals lower, there's not much that can stop that intense of snowfall.
The higher amounts of this wet, soggy snow brought nearly 2" of liquid equivalent, enough to turn the snow a shade of blue! The weight of the snow was enough to snap numerous tree branches, cause power outages for thousands and even enough to take down a few buildings and structures as well. Take a look at all of the pictures sent in by the viewers!
For more information, including a detailed look at snow reports for communities east of I35 click this link from the National Weather Service in La Crosse, WI: http://www.crh.noaa.gov/arx/?n=may0213
An interactive map of Snow Totals from May 2nd can be found here: http://mesonet.agron.iastate.edu/lsr/#ARX,DMX,MPX/201305021200/201305030459/0100
Storm Tracker 6 Chief Meteorologist