How Much Snow Would This Week’s Rainfall Have Produced if it was Cold Enough for Snow?
While snow is known to close roads, schools, and businesses; rain almost never causes the problems we've seen in the Northland in the past day. What if the precipitation over the past day has actually fallen during the winter? How much snow would all of the rain we've gotten translate to?
While there are a lot of variables in this equation, the average ratio used by meteorologists for rain to snow conversion is 10:1. This is for what is referred to as "average snow" as opposed to heavy, wet snow or dry, powdery snow. Based on the rainfall totals from around the area (found here), the average rainfall in the Duluth/Superior area comes out to about 7.7 inches. That 7.7 inches would translate to 77 inches of "average snow", which is 6.42 feet of snow.
While this number is rather impressive, the odds of seeing 7.7 inches worth of rain moisture in a 24 hour period during weather cold enough to create snow are very low. Cold air holds significantly less moisture than warm air, so while it isn't completely impossible to get 6 feet of snow in a day's time, a lot has to fall in place for it to happen.