How Much is Too Much: Heavy Snowfall Leads to Numerous Roof Collapses in NY

With the colossal snow totals that have amounted across the Great Lakes area, residents and local businesses have been warned of the possibility of collapsing roofs, as additional weight can compromise a building's structural integrity.

The Buffalo News reports at least 30 roof collapses have occurred since Wednesday, Nov. 19. There have been no injuries related directly to roof collapses, though two elderly patients died after being transported from the Garden Gate Health Care Facility in Cheektowaga, New York.

Though a small amount of rooftop snow can act as an insulator during cold winter months, an excessive amount can cause structural damage or collapse.

Determining how much snow is too much snow depends on the shape and age of the rooftop.

If a roof is pitched or slanted and in fairly good condition, heavier snow may be less of a problem. However, older and flatter roofs could easily succumb to the weight of the snow and fail.

"As snow sits on roofs, especially flat ones, it compacts and becomes more dense," AccuWeather Meteorologist Mark Paquette said. "When snow and ice falls on it, it becomes heavier."

A cold rain can also lead to heavier snow and more weight on a rooftop because when the rain falls it is then absorbed by snow already on the rooftop. As a result, the snow becomes even heavier than it was before the rain.

If the snow becomes too heavy, it can weaken the internal structure of a roof and cause damage or even cause the roof to collapse completely.

The type of snow that falls can also contribute to the likeliness of a roof collapse.

"There are different types of snow as well that can cause various damage," Paquette said. "A lighter, fluffier snow that falls with cold temperatures is a much different story than a wet, heavy snow with sleet and rain."

The more dangerous type of snow is the wetter, heavier snow due to its increased water content. This type of snow is most common around areas in southern New England.

To prevent a roof collapse or damage due to snowfall, keep tools handy that allow for timely and easy snow removal after a storm.