CONCORD, N.H. (AP) – Mark Mabra describes the roofs he’s been clearing like an archaeologist analyzing snow instead of soil: each layer tells the story of a winter that won’t quit.

“It snowed once, and they didn’t clear it. Then we had that wet snow that one time, and nobody did anything about that. And then we had another snow storm after that, and then it snowed again,” he said. “Now you’ve got snow, ice, snow, snow, snow, ice, and then snow again.”

Next up? Rain, snow and maybe some ice.

Record snowfall in parts of northern New England was forecast to get a bit deeper Tuesday and Wednesday, while rain elsewhere could aggravate a much worse problem: roofs caving in at schools, warehouses and other buildings.

William Degnan, New Hampshire’s fire marshal, has been urging home and business owners to clear roofs of accumulated snow and ice before the next storm. Many have learned that lesson the hard way, with either all out collapses or other signs of danger.

In Concord, elementary school pupils were kept from a section of the Dame School on Tuesday after custodians saw signs of potential problems in a flat roof over eight classrooms. In Holderness, children were sent home early from Holderness Central School after a custodian noticed some fire sprinkler heads had dropped a couple of inches from their normal positions, Principal William Van Bennekum said.

“Snow blowers were going, shovelers were going, we had help from volunteer firefighters, we had a teacher on the roof shoveling,” Van Bennekum said. “We have been shoveling snow for the last three weeks, but I guess we just couldn’t get enough off.”

A private airplane hangar attached to a house in West Ossipee collapsed Tuesday, crushing a Mercedes-Benz inside, WMUR-TV reported. Neighbors said that the home was vacant, so no one was around to notice the heavy snow that had built up on the roof.

Two Maine schools also have been closed because of school damage. Classes at Lebanon Elementary School were canceled Tuesday after a crack was detected in the ceiling, and on Monday, officials closed Sacopee Valley High School in Hiram because of cracks in 11 main support beams atop the gymnasium.

Several other buildings in southwestern Maine, including a storage building containing more than 100 cars, boats and RVs, also have collapsed.

Mabra, who owns a masonry business in Concord, said the threat of more snow and rain had his customers in a panic.

“The cell phone’s been ringing, the phone at home has been ringing. Yesterday, as soon as I hung up one phone, somebody called on the other, or both phones were ringing at the same time,” he said.

“A lot people are scared. What they should’ve done is had it taken care of before. But nobody expected this much snow anyway. And the way the economy is right now, people really don’t have the money, especially the elderly people.”

Jeff Staples of Staples Construction in Pembroke spent Tuesday morning clearing four feet of snow off a roof in Laconia before heading to a school in Concord. While some of his work has been repeat customers, most have waited until the last minute. In one home, he went into the attic and saw the rafters bending under the pressure.

In Montpelier, Vt., workers at Sarducci’s restaurant workers shoveled wet snow off the roof hoping to stay ahead of the sleet and freezing rain expected later in the day.

Some residents are doing the job themselves, when they can find the tools. Agway, which had been advertising roof rakes on its outdoor sign, still had nine left on Tuesday morning. Around New Hampshire many stores said they had none left.

Several buildings in the Montpelier area have partially collapsed, along with a number of barns, sheds and outbuildings in other parts of the state, said Montpelier City Fire Chief Gesualdo Schneider.

“The buildings that have not had any kinds of roof shoveling and are now carrying a heavy load,” Schneider said.

Even for strong roofs, snow and ice can be dangerous. Authorities in both Maine and New Hampshire noted snow can block chimneys and vents, allowing carbon monoxide to enter buildings, or can slide off and damage gas meters.

AP-ES-03-04-08 1826EST