JOHNSTOWN — An avalanche of commercial roof collapses continued Thursday – with at least three major cave-ins – under the steady weight of 21/2 feet or more of snow causing tens of thousands in property damage and risking lives.

Emergency services officials reported no injuries from the latest falls, though at least one cow reportedly was killed when a barn roof in New Centerville crumpled.

Other collapses were reported at a Johnstown-area warehouse under renovation and at a Meyersdale barn.

“In the last 50 years, we haven’t had a winter like this – not snow like this all at one time that doesn’t melt,” said Rick Lohr, Somerset County Emergency Management coordinator.

He offered some theories as to why larger buildings seem to be the most problematic.

“Those buildings may not have a lot of heat inside, and it’s not rising to roof level to melt the snow,” he said Thursday. Further, many of these structures have flat roofs, so the snow has nowhere to go.

Thursday’s roof cave-ins included:

n At 5:03 a.m., a barn collapsed at 882 Chippewa Road in the New Centerville Area. About 20 cows were inside and some were trapped.

n About 6 a.m., a former carpet store roof collapsed in the 400 block of Ohio Street in Lorain Borough.

Several blocks of Ohio Street were closed to traffic into the afternoon while an excavator razed the central part of the building, leaving wings on either side.

n At 8:41 a.m., the Meyersdale Fire Department was dispatched to a barn collapse at 3096 Pine Hill Road, Summit Township.

That was just Thursday.

Earlier in the week, in Somerset County, collapses were suffered by a CVS Pharmacy distribution center, at Georgian Place and at another barn, Lohr said. And a woman was injured knocking ice off an awning.

On Ohio Street, Lorain fire Chief Jim Rutledge said a 50-by-100-foot section of the roof collapsed in the center of the building, a former carpet store and former variety store at Oakland Avenue.

He said he believed the collapse was due to the snow.

Rutledge said the owner could have tried to remove the snow, which may have averted the collapse. He termed the center of the structure a total loss.

Arriving crews were met by an odor of gas, and Dominion Peoples cut the natural gas flow.

Later in the morning, 10 sandbags were called for to prevent any liquids from spilling into a nearby creek.

Building owner Ken O’Connor of O’Connor’s Heating, Air Conditioning & Plumbing was renovating the structure for use by his business, fire officials said. They said workers had spent months putting on a new roof in 2009, and recently painted the outside of the building.

O’Connor did not return a call for comment.

Experts asked homeowners to use caution when dealing with snow and ice on their homes.

Parrish Varnish, owner of P. Varnish Contractors in Geistown, said this winter has been busier than most.

“This year, we’re getting a lot more gutter repair and insurance jobs because soffit and fascia is coming down with the gutters,” he said. In the past two weeks alone, he has turned in 15 claims to insurance companies.

Snow and ice buildup can be insidious.

Varnish said the buildup prevents snow from moving off the roof, trapping the water and forcing it under the shingles, up the roof line and eventually into the home.

“As a result of that, you end up with wet interior walls, wet roofs, carpets and so on and so forth,” he said. Leaky roofs will have to wait for warmer weather to be fixed.

Call a professional

He recommends calling a professional to remove ice dams: “It’s pretty dangerous.”

Lohr concurs.

“People should exercise caution. I wouldn’t recommend anyone getting up and cleaning a roof if they’re not experienced. Get someone who knows what they’re doing and be sure to work with a partner,” he said.

Varnish said his five employees use a tool called a roof rake to clean off snow and ice.

“If you go up with a shovel, you could damage the shingles,” he said. “A roof rake has wheels to keep the rake a half-inch above the roof line.”

He also has heard of people throwing rock salt or calcium chloride on their roofs to melt the snow. “They’re causing more problems in the long run,” Varnish said, because the corrosive chemicals will eat up shingles.

Actually, homes with poor insulation might be faring the best in avoiding snow and ice damage. Lohr said that heat escaping the home can cause melting, avoiding roof buildup altogether.

He said some business owners might take a lesson from this winter and add more supports to their roofs once the weather warms.

Lohr is not as concerned for homeowners, whose roofs generally are well sloped. Even mobile homes and their flat roofs don’t overly concern him because of their small area.

He does see light at the end of the tunnel

– literally.

“The bottom line is,” Lohr said, “we’ve had actually three storms in a row and not any real sunlight. You’d be surprised what would happen in a day or two (with sun).

“I just hope it isn’t any worse than the day before, that it gets better,” he said.