On Thursday afternoon when Paul and I were discussing the potential snow accumulation we debated a couple of things. First off was how far to the west the warm air would push in from Wisconsin to change the snow to rain in the vicinity of the Twin Cities.
Since the high temperature was sixty-eight degrees on Wednesday, we also talked about the possibility of the snow melting as it hit the ground. We are old enough to remember what happened on October 31, 1991. Falling snow modified the surface temperature and we were on are way to a record snowfall.
When the snow began to fall very early Saturday morning it fell at a fast enough rate to quickly cool the surface and within in less than two hours there was a sufficient coating of snow to create a skin temperature for rapidly accumulating snow.
While the snow did melt on the roadways for another hour or two, by daybreak the intensity of the snowfall rate was enough to keep the temperatures ideal for a heavy, wet accumulation.
Soil temperature over sod at the St. Paul Campus for the last five days. Check out the dip in temperature around 4am. The lowest line, in purple, is near the surface
Climatologist Greg Spoden and I looked backed this afternoon on the autumn snowfall of 1991. On October 31st slightly more than eight inches of snow accumulated by midnight. By the time the Halloween Blizzard had ended the snowfall talled up to a record twenty-eight inches.
Amazingly, a string of mild days in Novemer of 1991 took the snow depth at the Twin Cities International Airport down to a mere trace by November 20th. A pre-Thanksgiving snowfall and a post-Thanksgiving snowfall delivered a trifecta of snow events that resulted in a whooping total of 46.9 inches of snow for the month of November in the Twin Cities.
The post-Thanksgiving snowfall on November 29/30, 1991 was greater than thirteen inches. At month’s end the snow depth was back up to sixteen inches on the flat.
It will be interesting to see how much snow is still around by the end of the week.
For those who like to probe into the meteorology, here is a link to the storm that we just endured. A recap from the Chanhassen NWS.