BOSTON -- Close to 100 buildings' roofs have buckled and collapsed under the weight of heavy snow and ice this week, but no one has been injured, according to state officials.

The Massachusetts Emergency Management Agency said 92 roofs have either fully or partially collapsed, and 13 of those were reported on Friday.

Especially hard hit have been flat-roofed commercial buildings, stores and schools, although at least two homes and two barns have also collapsed.

Workers at a Comcast facility in Westford were evacuated early Friday while emergency crews checked on reports of a roof collapse threat, and another barn imploded in Hopkinton as Bay State structures continued caving in under heavy snow at a record rate.

Photos: Mass. Roof Collapses

The Centerville Elementary School on Hull Street in Beverly was also evacuated after a crack was found in the building. Although there was no collapse, students were moved to another elementary school as a precaution.

Workers also arrived at the McCall Trucking Company on Waltham Street in Wilmington to find a significant portion of its roof had caved in. The collapse occurred over the part of the building leased by Brooks Interiors and the electricity and gas were shut down until inspectors could check out the safety of the rest of the building.

Roof concerns at Wal-Marts in Chelmsford, Worcester, North Attleborough and Northampton forced those stores to close as precautions on Friday. Wal-Marts in Westfield, Leicester and Hudson, N.H., were closed for a time this week, but have reopened. The North Attleborough store is expected to reopen Friday night.

A shopping plaza at the corner of Route 126 and Eliot Street in Ashland was evacuated Friday afternoon because of roof concerns after a worker reported hearing a cracking sound.

State emergency officials said there have been dozens of roof collapses since Wednesday, when two powerful winter storms dumped at least another foot of snow in some Massachusetts regions.

Two horses escaped the barn that collapsed on Fruit Street in Hopkinton early Friday. No one was injured. The couple who owns the property awoke to find the animals trapped.

"When we got here there was really tough access 'cause of all the snow. The roof had collapsed into the first floor of the barn. The horses were actually located in the basement. When we were able to access that area we found that it was structurally sound and we were able to free the horses from there into a safe area," said Hopkinton Deputy Fire Chief Steve Slaman.

Gov. Deval Patrick said he is pursuing possible federal relief for Massachusetts after the nasty one-two punch of snow and freezing rain socked the state, causing the roofs to collapse and damaging homes, businesses and schools.

Patrick said Thursday that he's told the Massachusetts Emergency Management Agency to work with the federal Small Business Administration to determine the state's eligibility for a disaster declaration or economic injury declaration.

Federal help couldn't come too soon in communities across the state where successive storms over the past month have contributed to heavy snow buildup on roofs that were collapsing at a rapid rate all over the commonwealth.

Students and staff were safely evacuated from an elementary school in Georgetown Thursday, one of several schools across Massachusetts threatened by heavy snow and ice buildup on roofs. No one was injured in the collapse at the Perley School at 51 North Street in Georgetown, fire officials said.

"We received a phone call actually from one of the neighbors asking if we were aware there was a hole in the roof at the Perley School because we didn't hear anything and we didn’t see anything at the time. We had no way of knowing if anything had happened," said Georgetown Superintendent Carol Jacobs.

All Georgetown schools were closed Friday so inspectors could assess the buildings' safety and crews could continue to clear snow.

Students at the South Shore Charter School in Norwell were sent home early on Thursday and Peabody schools remained closed Thursday after two days of snow as crews assessed the danger of roofs overburdened with weeks of heavy, wet snow and ice accumulation. Hingham and Hamilton-Wenham districts also canceled school over roof concerns.

Patrick was also urging homeowners to be extra vigilant about the threat of heavy, wet snow on their properties.

A horse riding arena in Bolton caved in Thursday, as did a Reading home. A father and son were inside the home at the time, but neither were hurt.

The family said they started hearing creaking noises a few days ago. When they saw the ceiling start to bow, they started removing valuables from the house.

"It was a very loud pop at that point and it just -- that's it. I heard things crashing and then I just wanted to get out," said homeowner Rob Filipek, who escaped along with his teen son, Andrew.

Earlier on Thursday, a 91-year-old Chelsea woman was evacuated from her Vernon Street home in Chelsea as a safety precaution after the building next door to her collapsed under the weight of heavy snow on its roof.

At least six stores in a strip shopping mall in Lincoln were closed Thursday following a roof collapse overnight at Donelan's Supermarket.

The governor said if homeowners, tenants or businesses have concerns about the structural integrity of their buildings, they should leave immediately and call 911.

Structural engineers said creaking noises may indicate a roof has been weakened and may be ready to collapse.

Roofers said they have been working around the clock to help homeowners clear away some of the icy accumulation.

"You gotta get up there and shovel it off," said Dan Essary of Lyn Roofing. "We have five phones going in the office non-stop, sunrise to sunset."

Forcasters said there will be another snow storm this weekend.