A Winnipeg homeowner is urging others to clear snow from the roofs of their homes, after her garage roof collapsed under about a foot of snow.

Sharon Segal says she discovered the collapsed garage roof when she came home on Monday.

"Really, I can't believe all the snow and that it did that. I was just stunned," she told CBC News on Tuesday.

Segal said she had thought about removing the snow, about one foot deep, from the garage roof last week.

"We're kicking ourselves for not doing it," she said.

She said she's grateful that no one was in the garage when the roof collapsed. Her family's cars were not inside the garage at the time, and she said the structure is covered by home insurance.

"We were just so surprised," she said. "Obviously, it was heavy enough that it did this."

As fluffy as it looks when it falls to the ground, snow can actually be pretty heavy, says Dimos Polyzois, a structural engineering professor at the University of Manitoba.

Polyzois said 20 centimetres of snow on a 100 square-foot roof has an equivalent weight of an elephant.

"If you have a 1,000 square-foot roof, it's like having about seven elephants walking on your roof," he said. "That's the weight of snow."

Polyzois said buildings that are properly designed should withstand 115 centimetres of snow.

Ice dams will add more weight to the roof, but Polyzois said structures are more often to blame than the weight of the snow itself.

"The most common cause of these roof collapses is poor design," he said.

Still, Segal said it doesn't hurt to remove a winter's worth of snow from rooftops before something happens.