The winter of 2012-13 could be the time for the Midwest to get
hit by heavy snow and ice storms, which can leave large amounts
of snow and ice on roofs of agricultural buildings, according to
University of Minnesota agricultural engineers Larry D. Jacobson
and Kevin A. Janni. They explained that despite the recent large
snowfall that left over a foot of snow and ice on roofs in
central Minnesota, most of that snow came off roofs during the
warmer temperatures that followed. But with colder temperatures
expected, don’t count on future snowfalls sliding off. Trusses
and rafters must support the increased weight, or roofs may
collapse. University of Minnesota Extension points out that
agricultural buildings with well-designed roofs cannot take
excessive (greater than 4 to 6 ft.) amounts of snow. A safe
amount of snow to have on a roof over an extended period of time
for the upper Midwest (where snow loads are typically at least
20 lb./sq. ft.) would be 4 ft. of dry snow or 2 ft. of wet,
heavy snow and ice. The M