Heavy snow overhead

Snow roof.jpg

The roof at the Huttner Weather Lab supporting a good foot of snow these days.

Look up: There are probably thousands of pounds hanging over your head right now.

Our heavy December snows have stacked up on lawns fields and rooftops around Minnesota. The first thing I noticed upon returning to the weather lab from Arizona over the weekend was the heavy blanket of snow on the roof.

It is interesting to calculate the weight of the snow on your rooftop. One resource I found suggests that at a 10:1 snow to water ratio one inch of snow weighs about .52 pounds per square foot.

Let’s say you have a rooftop that measures 20′ by 50′, or about 1,000 square feet. 10″ of snow on your rooftop weighs about 5.2 pounds per square foot. That’s about 5,200 pounds of snow sitting on your rooftop. I have seen rooftops that seem to have more that 1 foot of snow depending on wind exposure. Two and a half tons is a lot of weight on your roof!

The good news is roofing codes and truss systems are built to handle heavy snow loads. Ice dams can be another issue in winters with heavy snow. The roof rake comes in handy in years like this.

Our arctic chill looks to hang on this week. Wednesday’s Alberta Clipper appears to be aimed primarily at eastern South Dakota, southwest Minnesota, and Iowa. Those areas may see the best chance of a dry powdery 2″ to 4″ of snowfall. The Twin Cities may be close enough to catch a coating of fresh snow with this system. Stay tuned for updates on the track.