Anchorage’s reported roof failures rise to at least 16 under heavy snow and ice

Anchorage municipal officials say at least 16 roofs have buckled in the city this winter under heavy snow and ice, and they’re wary of additional collapses after another storm dropped more snow this weekend.

The number of failed roofs is far more than the five collapses that have made headlines, including one at a South Anchorage gym that caused a woman’s death. The new, expanded list adds 11 more, including partial failures at large warehouses and collapses at smaller structures such as carports that haven’t received much attention.

That updated statistic likely makes this winter the most significant for roof damage since at least the winter of 2011-12, said Ross Noffsinger, acting building official for the municipality. City officials said Monday they haven’t yet estimated the total damages from this year’s collapses.

“This is probably the biggest grouping of failures we’ve had (since then),” said Noffsinger, referring to the snowiest Anchorage winter on record when 134.5 inches fell.

At least 14 roofs buckled that winter, according to reports in March of that year, though it’s possible there were more. City officials said Monday there’s no official data for how many actually collapsed.

This winter featured near-record snowfalls in December, followed by additional big dumps as the season dragged on. On Sunday, forecasters recorded 100.5 inches of snowfall in Anchorage, only the 10th time that’s happened since the winter of 1916-1917, according to Brian Brettschneider, a climate scientist with the National Weather Service.

[Weekend snowfall pushes Anchorage’s season total over 100 inches]

Occasional warm-ups contributed to melting and severe ice damming in some cases, often concentrating the weight on flat roofs with poor drainage, experts have reported.

Previously reported roof failures this winter included the Turnagain CrossFit gym in February that killed one person and trapped two others, a partial collapse at the Northway Mall, a transmission shop off Dowling Road, a thrift store near downtown and an electrical contracting company off the Old Seward Highway and East 66th Avenue. In Mat-Su, part of the roof over the Palmer Public Library gave way on Feb. 15. A family inside and several staff members escaped unhurt.

Warm days recently have helped melt snow off roofs, but several more inches of snow dropped on Anchorage over the weekend. The snow was fluffy, so it melts down into a very thin amount of water and is relatively light, Brettschneider said.

Still, Noffsinger said, it’s possible more roofs will fail before winter finally ends.

“I won’t say we’re in the clear,” he said. “Spring is coming slow and roofs aren’t unloading fast.”

Newly reported failures

Engineers earlier this winter said that the vast majority of houses are safe under the snow loads, while the reports of major damage have largely been limited to commercial buildings with broad roofs.

The collapses this winter have prompted Anchorage building officials and the fire department to issue multiple warnings and guidance on clearing snow from roofs, particularly wooden roofs at aging commercial buildings.

Besides CrossFit, there have been no reports of injuries, Noffsinger said.

The full list of collapses, provided by Noffsinger, combines responses from the Anchorage Fire Department data and building code officials, Noffsinger said. Fire officials reported last week at the Anchorage Assembly’s committee on public safety that 19 structures had collapsed. But one of those was a deck, another turned out to be an incorrect report, and a third is still under evaluation, according to the list.

[Municipal inspectors advise owners of some older commercial buildings to clear snow from roofs]

Previously unreported roof failures included:

* In December, a broken roof beam caused the temporary closure of the Lucky Kitchen restaurant and Lucky Market Alaska convenience store near Arctic Boulevard and International Airport Road.

* In March, the city responded to roof trusses that failed at Sand Lake Automotive at 1307 E. 74th Ave. That was related to long-term wood rot and leaks, Noffsinger said. The flat roof sagged several inches, but was safely propped up to await repairs, he said. The business had to close down for more than a week while extra support was added to the roof.

Sand Lake Automotive, which leases the building and has operated for 45 years, will have to leave the building in May for the permanent repairs, said owner Tim Mason. It will have to find a new home if it will survive, he said. “We are desperately looking for a building,” Mason said.

* Earlier this month, an entry canopy at Faith Christian Community church at 4240 Wisconsin St. collapsed because of failed roof trusses, while another entry canopy was compromised, Noffsinger said. A daycare there had to close for a couple of days until the compromised entry could be fixed, he said.

* On an unknown date, the flat roof above an internal stairway collapsed at H2oasis Waterpark at 11030 Chelea St., off O’Malley Road.

* Around March 20, several roof beams broke at Metrie, a wholesale lumber and moulding supplier at 2503 Arctic Blvd. near Fireweed Lane. The wooden beams were supported by metal trusses, but spanned a large area, said Walter Warren, the store’s manager. The large roof didn’t collapse or leak, but it’s sagging in a corner of the warehouse, he said. It’s been shored up under an engineer’s guidance until further repairs can be made.

The building was built in the early 1960s, Warren said. Metrie has been there for decades, but snow on the roof hasn’t apparently been a problem until this year.

It’s possible that an abutting building constructed decades ago allowed snow on Metrie’s sloped roof to become trapped, creating a concentrated area of weight, he said. No one was apparently in the building when it happened, and Warren evacuated the area and contacted city officials.

“The engineers don’t want us going onto the roof to try to remove that snow, so all we’re doing is shoring it up and waiting for mother nature to get it melted off so we can get a better assessment,” he said.

‘We’re not done’

The full report of additional roof collapses is “alarming,” said Assemblyman Kevin Cross, co-chair of the committee.

It’s been fortunate that the collapses haven’t led to more injuries or fatalities, he said.

Cross, a real estate broker, said the assembly isn’t considering making any changes to city building codes, but it’s important that property owners keep a close eye on their roofs.

Emergency officials have warned that property owners should consult an engineer if they see problems such as new or worsening cracks on walls, “nail pops” on finished surfaces, doors or windows that have become hard to open or close, or sagging structural members.

“We’re not done with this issue,” Cross said. “The buildings will get older and we’ll have occasional winters with extreme heavy snowfall, so this will occur again if we don’t do anything.”

The additional collapses continue to show that wooden roofs are a primary concern, along with metal plates that help hold roof beams together but can eventually fail, Noffsinger said.

Property owners and engineers should pay extra attention to buildings with those roofs, which are common throughout Anchorage, Noffsinger said.

“I don’t think any failures were steel structures, they’re all wood,” Noffsinger said. “Most are all truss failures. And the metal plates in some cases does not appear to be adequate to account for all the various factors that can compromises the structural integrity of a truss.”

Scott Hamel, dean of the civil engineering department at the University of Alaska Anchorage, said property owners this summer should take steps to address significant ice damming. The solutions could include more ventilation in roofs, or changes to insulation in the roof, he said.

“An expert can look and say you need more insulation, or less, or more ventilation, which is usually better than more insulation,” Hamel said. “It has to be done in summer. You can’t fix ice damming in winter when the ice damming is actually happening.”

Noffsinger said the city for the first time plans to issue specific snow-removal guidance next winter explaining when commercial building owners and others should consider removing snow from their roofs, with special instructions for different types and ages of buildings, he said.

“We learned a lot this winter and we know we have to give a more nuanced message,” he said.