MINNEAPOLIS (WCCO) — A few weeks ago came warnings about the danger of ice dams, and now there are reports some roofs are collapsing under the weight of rain-soaked snow.

Two roofs have collapsed in just the past two days, and one was at a popular building on the Minnesota State Fairgrounds.

When St. Paul firefighters arrived Tuesday evening, they found the roof on the southeast corner of the Cattle Barn had fallen in, taking part of the brick wall down with it.

Some vehicles stored in the building were damaged, but no animals or people were there. The rest of the building was deemed safe.

A few minutes later — around 6:40 p.m. — another roof collapsed over a pool at a Super 8 Motel in Shakopee. The pool area was closed earlier in the day when the roof was discovered to be sagging; Shakopee police say no one was hurt.

It can be a delicate balancing act this time of year, particularly for flat roofs. Rain, like what’s been falling on Wednesday and is likely to repeat on Thursday, can get absorbed by snow pack that’s leftover on the roof, almost like a sponge.

Rueben Saltzman, owner of a home-inspection company, says some flat roofs with poor drainage may be near their design limits this year.

“On average the snow is about 2 feet deep,” Saltzman said. “Somewhere between about 35 and 40 pounds per square foot. Roofs are designed by code; the code minimum is 35 pounds per square foot.”

Most pitched roofs — like on a typical home — hold less snow and have drainage.

“If you see a bunch of bare shingles on your roof, you probably don’t have anything to worry about,” Saltzman said.

In about six weeks, the Minnesota Horse Expo is scheduled to take place, in part, in the Cattle Barn. WCCO’s Mike Augustyniak talked to the organizers and they said, as of now, that event is scheduled to go on as planned.

Mike Augustyniak