Another day in the Winter of 2019, another day of headlines including farm building collapse in the Midwest. This time the story was on a farm near Eleva, Wisconsin but as far as I can tell, the collapses happened a week ago, the Sunday morning of February 24th. You can follow a link to the Eau Claire Leader Telegram story by clicking on the photo below.
Back up to current events, the past 72 hour snowfall looks like it hit mid-Minnesota and mid-Wisconsin with some snow and some heavy snows in some pockets, including the Stillwater, Minnesota to St. Croix Falls, Wisconsin area.
What’s more telling than the seasonal snow fall total is the estimate of the current loads on roofs, and by load I really mean the weight of all precipitation on the roof (Snow, Ice, Slush, trapped water, etc.) but I know of no source for giving that information. The National Snow Analysis site through NOAA does give a map of Snow Depth which gives some measure of current snow on the ground. From the current map you can see that much of Wisconsin and many parts of Minnesota are in the dark blue band which is a range of 20″ to 39″ of snow.
A middle of the road “guesstimate” for the density of “typical” snow in this area would be 22psf (based on ASCE 7 formula), so using that guesstimate, the range of weight for 20″ to 39″ of snow would be 37psf to 72psf of snow. Of course, snow isn’t typical and sometimes Roof Snow Loads may exceed Ground Snow Loads due to certain material features and geometry of the building.
I’ll be traveling today and tomorrow to Louisville, KY for the 2019 NFBA Expo where I will be speaking on Thursday morning about snow loads on Post Frame buildings. If you’re going to the Expo this week, I hope to see you there! The current outlook for the region shows some new snow on the East side of Lake Michigan (in Michigan) and then some snow coming through the Midwest toward Louisville ending Friday morning March 8th and some more snow in the Midwest over the coming weekend.