The University of Minnesota Extension Service warned yesterday that last week's heavy snow across the Midwest could result in structural failure of farm buildings. Several barns have already collapsed in Minnesota due to snow load, resulting in the death of dozens of cattle.
Northern farm buildings are generally designed to withstand snow and ice loads of about 20 lb/sq ft, say Larry Jacobson and Kevin Janni, U of M ag engineers. But this level of loading is not intended to last all winter. There is a fatigue factor.
A roof might be able to support the designed snow load for several days or a few weeks, but probably no more than 30 days, they say.
If roofs are carrying heavy snow, producers have several options. They can physically remove the snow load from above, or pump extra heat into buildings from below in hopes of melting the snow. Each has its inherent risks.