At least three roofs in the Fairbanks area collapsed under the weight of particularly wet snowfall this weekend — the roof of the Sourdough Fuel bulk plant, a commercial building on Leasure Street and the Ester Volunteer Fire Department building.
The roof of the commercial building on Leasure Street collapsed with a loud bang right after 4 a.m. Tuesday, Fairbanks Fire Chief Tod Chambers said. A person who was inside heard the noise and safely got out. The fire department responded to the emergency call at 3661 Leasure St. and secured the building, effected by the heavy snow weight, Chambers said.
The Ester Volunteer Fire Department building experienced the same issue earlier on Sunday morning, when staff heard a sound one of them described as “the loudest washing machine noise,” Fire Chief Jeff Conner said. The roof collapsed at 1:45 a.m. under the snow weight, pinning three fire trucks but hurting no one. The department plans to get their operations running by Thursday, while Chena Goldstream and University fire departments are responding to emergencies in the area.
Back on Saturday morning, the roof above the main warehouse of the Sourdough Fuel’s bulk plant fell under the snow weight as well. No injuries or spills were reported, and no one was inside the building, Chambers said. The store at 418 Illinois St. that sells lubricants, coolants, bulk fuel and fuel-related accessories is currently closed.
Before this weekend, Fairbanks saw a couple of other roofs collapsing, said Clem Clooten, a building official for the city of Fairbanks. In an average winter, anywhere between two to five buildings experience the issue, he added.
“I would say it is not common at all,” Clooten said. “We have many buildings and very few collapses. Very, very, very few collapses.”
Is your roof safe?
For a roof to collapse, something has to be impacting the support structure, and most of the time it’s snow that adds a significant amount of weight to buildings, Chambers said.
Clooten estimated the snow load in the area to be about 30 pounds, eight pounds more than in the beginning of March.
Roofs in Fairbanks are designed to withhold the weight of 50 pounds per square foot, Clooten said. Structures that don’t meet that requirement can be upgraded.
To find out whether a roof meets safety standards, residents need to know when the building was built and under which circumstances and code, Clooten said. If you doubt your roof’s resistance, you can call a structural engineer to inspect it, preferably before snowfall. Moving the snow off the roof is also a great way to feel and be safer.
The winter load design follows the International Building Code and the International Residential Code, but Fairbanks made amendments to adjust to local conditions, Clooten said.
“We increased the load to 50 pounds compared to 30, say, in North Dakota, because they don’t get that much snow as we do,” he said.
If Fairbanks winter conditions change over the years, the code would be changed to accommodate that — and increase the snow load if necessary, he said.
Why was the snow so heavy?
This past weekend, Fairbanks roofs had it bad. After an already snowy March, more than 14 inches of snow dumped on Fairbanks on Saturday and Sunday. By Monday, the depth of the snowpack built up over winter hit 40 inches, second highest depth for April 4, according to the National Weather Service. But it’s not the amount of snow that made it so heavy.
“For a roof collapsing, what really counts is the water content of the snow,” said Rick Thoman, climate specialist with the Alaska Center for Climate Assessment and Policy at the University of Alaska Fairbanks. “In other record years, the snow was much fluffier,” he said.
Several factors made the snow so wet. A winter storm came with a southwest wind blowing from the Bering Sea, large areas of which are not covered by ice. Those open waters gave an additional source of moisture for the storm, Thoman explained. The winds blew it to the Interior, avoiding the Alaska Range mountains, which could have stripped the storm of some precipitation but didn’t.
Already saturated by water, the storm also paired with the unusually warm temperatures which made the snow more dense, Chambers said.
“It’s always a combination of different features that produce extreme events like this,” Thoman said.
Contact staff writer Alena Naiden at 459-7587 or follow her at twitter.com/FDNMlocal.