Feb. 19, 2008 — The series of winter storms that rolled through Lassen and Plumas counties over the last month left some people shoveling snow off roofs. The accumulated rooftop snow amounted to several feet in parts of both counties, especially Westwood, where inmate crews from the Lassen County Adult Detention Facility cleared school roofs.

Henry Bietz, Westwood School District superintendent and principal at Westwood High, said inmate crews were scheduled to shovel snow for the third time during the Presidents Day holiday on Monday, Feb. 18. Crews had already shoveled on Monday, Feb. 11, a school holiday. Schools was closed for snow shoveling on Feb. 7.

“We had to close the schools because there were so many water leaks because of ice dams,” Bietz said. “There was not a lot of damage. It’s just more of a nuisance than anything else.”

Water was dripping down the walls in classrooms and hallways, he said.

“If we hadn’t removed the snow we would have had some damage.”

Bietz said the snow melts over classrooms, where the roof is warm, but over the eaves and overhangs, where the roof is cold, the water freezes and builds dams 6 inches to a foot high.

The melting snow then has no place to go and backs up the roof until it hits a seam, where it leaks into the buildings. With up to 6 feet of snow on the ground and 2 to 3 feet on rooftops, no building in Westwood is free of the problem, except those with metal roofs designed to shed snow.

“Homeowners have the same problem,” he said. “The only ones that don’t are vacant because the roof temperature is the same all the way across. “This is probably the most snow we’ve had on the ground and around in 15 years,” he said. “It gets too much for our small maintenance crew. We need to thank Jason (Langslet) and rest the crew and so does the rest of the community. They work really well as a crew and we really appreciate their help.”

Lake Almanor
With similar amounts of snow in Plumas County, the building and planning department had workers taking samples in the Lake Almanor area in early February. According to Plumas County Building Official John Cunningham, those measurements showed around 51 pounds per square foot of snowload.

The Peninsula Fire Protection District was monitoring the snowload on the roof of its #2 station. As of Feb. 5, that measurement was 66 psf.

Design parameters can vary considerably across the counties, from a low of 40 psf in Susanville, Belden, Tobin and Twain to a high of 100 psf in Westwood and 200 psf at Bucks Lake, La Porte and Little Grass Valley.

Currently, Chester has a load requirement of 100 psf. Prior to 1980, the requirement was 80 psf.

Longtime residents may remember a rash of roof collapses throughout both counties during the winters of 1993 and 1995.

“We’re a long ways from those kinds of loads,” said Cunningham. “We learned from them that a good rule of thumb for Chester was to shovel if you had 6 feet of snow, 3 feet in areas like Quincy, Greenville and Graeagle.”

“We’re not recommending shoveling roofs in the foreseeable future,” he said.

Licensed structural engineer Jim MacIntyre, owner of Oak Knoll Engineering in Quincy, said folks probably don’t need to worry about the structural integrity of their homes.

One exception would be if you live in a localized area like Upper Siberia (as the West Shore of Almanor is often referred to). Another example is nearby Warner Valley, which has a snowload of 125-150 psf. Other causes for caution, said MacIntyre, are the age of your house and whether you have experienced problems before.

Areas you might want to pay attention to are places where one roof sheds snow onto another roof and where roofs shed onto decks, particularly if the decks are elevated, said MacIntyre.

That seems to have been the case when a building at the Susanville Indian Rancheria collapsed in January 1992. According to news reports, the building’s relatively flat roof was overloaded with snow that had slid off the gym’s steeper roof and become trapped on the smaller roof.

Besides obvious signs of building distress like bowing posts, sagging roofs or broken roof members, other telltale signs are doors or windows that won’t open and close properly.

When Leonard’s Market in Portola collapsed in January 1993, the first sign of trouble was a front door that wouldn’t open, according to press reports at the time.

Overhanging or cantilevered roofs may also be vulnerable. An overhanging porch gave way at the Hamilton Branch fire station in January 1993, for example. A poorly designed unreinforced masonry building in Quincy suffered a progressive failure when its cantilevered entryway gave way, pulling out a section of interior roofing, leading to total collapse.

Loud sounds may also signal structural settlement. According to eyewitnesses, a “loud cracking sound” accompanied the appearance of a fissure in a roof beam in the Lassen High School boys’ gym in February 1993.

“I looked up and saw this huge crack in the beam,” said one observer. “It was about 30 feet long and maybe 6 inches wide at its widest point. The beam was swaying about 12 inches from side to side.”

MacIntyre pointed out that folks might want to look at other structures — outbuildings, woodsheds, stand-alone canvas carports, awnings, even RVs — that are not designed for the county’s snowload.

Both Cunningham and MacIntyre caution that if you do decide to shovel your roof you should take certain precautions. Shovel equally on all sides so that the snowload is evenly distributed.

Do not shovel all the way to the roof surface, as you could damage it. Instead, leave several inches of snow, said Cunningham.

Watch for electrical items, skylights and the like, and be careful where you toss the snow — you don’t want to bury propane tanks, vents or electrical hookups.

And never attempt to shovel a metal roof; they’re designed to shed snow — and perhaps you along with it.

Supervisor Sherrie Thrall, who represents the Lake Almanor area, warned constituents in an e-mail, “If you should decide to hire someone to shovel for you, please be aware that there are some unscrupulous people charging exorbitant rates operating in our area. Shop around; ask your friends and neighbors for referrals. Many of our excellent local contractors can coordinate this service for you.”

For a description of how to check the snowload on your roof, visit peninsulafire.net. For specific snowload requirements in Lassen County, call the Lassen County Community Development Department at 251-8269 with a specific parcel number.