CHARLESTON, W.Va. -- One gallon of water weighs more than eight pounds -- and for at least two homes in Nicholas County, the 20 inches of snow stacked on their roofs from superstorm Sandy was just too much.

An elderly woman was rescued from her trailer in Canvas after the roof collapsed following high winds and heavy rain and snow Monday night and Tuesday morning. West Virginia National Guard members rescued the woman, according to the Nicholas Chronicle.

Guard members also rescued a family when their roof collapsed in Cottle, said Carla Hennessey, Nicholas County's director of emergency services.

No injuries were reported in either incident, Hennessey said, but both homes were completely ruined "due to the weight of the snow on the roof."

Other homes and businesses across West Virginia suffered roof damage from the storm. Hennessey said because Nicholas County was expecting more snow from Sandy, there "is no way to travel" to repair such damages.

Jay Marino, owner of Charleston contracting company Al Marino Inc., said Tuesday that his workers can't repair homes until power is restored, which utility companies have said would take days.

Marino said he and one of his technicians tried to get to a customer's home on Childress Road Tuesday, but numerous fallen trees and downed power lines stopped them.

Marino said he didn't get any calls Tuesday about collapsed roofs, but he did get quite a few about water leaks coming from roofs.

The snow created ice dams, which probably led to the roof collapses, Marino said.

An ice dam occurs when water builds up behind a blockage of ice, he said. When snow melts rapidly, the water can be diverted back up under roof shingles, Marino said. The snow melts almost as fast as it accumulates, he said.

"Even though the roof may be intact, and there may not even be a bad place in the roof, it's just caused by this type of unusual storm with a lot of heavy, wet snow. It sticks, and at the same time, it's trapping water," Marino explained.

"You can imagine, with the square footage of a roof, if you have 10 inches of not just snow, but moisture-laden snow, that's a tremendous amount of weight, and roofs are not really designed to withstand that."

But people who wake up to a snow-covered roof shouldn't panic, he said.

There are two ways to check the roof's safety without actually risking climbing on top -- which Marino never recommends.

First, roofs are symmetrical, he said.

"If you stand outside and look at your roof, it'll telegraph if there's a problem. It should be even with the road line," Marino said. "If you see a dip or swag, you could have a potential problem."

People worried about their roof caving in could also go to their home's attic and check the boards to make sure they're even and straight, Marino said.

Besides those suggestions, Marino said people should always contact a professional first. Professionals can add more boards to the home's structure for extra support and assurance, he said.

If a roof does collapse, Marino said insurance companies won't hesitate to authorize a professional to put up a temporary tarp and support beams as soon as damage is reported.

Marino said a significant concern with Sandy is the timing. Usually by the time snow falls as much as it did during this storm, West Virginians have already cleaned the leaves out of their gutters.

Not with this pre-Halloween storm, where a buildup of autumn leaves would trap snow in gutters and on roofs, he said.

"Most people probably hadn't done the maintenance they typically would've done by now: removing leaves, starting furnaces and being prepared for this kind of storm," Marino said. "People got ready [for the storm], but there's maintenance that couldn't be done in time."

Roof collapses shouldn't come as a complete surprise to residents, however, Marino said. Warning signs include sounds, such as "popping and cracking," Marino said, and a split in the home's ceilings. Also, if a roof is old, it may be time for a new one, he said.

According to the National Association of Home Builders, your roof should be inspected by a qualified roofer every three years. Marino further advised getting an inspection after a hailstorm.

"No roof is built so strong that it doesn't fail over a period of time," Marino said. "Shingles can be damaged by a hailstorm and we don't even know it. They could be cracked, have the asphalt coating knocked off of it. Shingles are very susceptible to heavy types of rainstorms."

Marino said his contracting company is still not finished fixing damage caused by the summer derecho. While there are six months of scheduled derecho fixes to repair, Marino said his men are ready to help homes damaged during this storm.

"This was truly the perfect storm. Last week we were doing air conditioning calls, this week we're trying to get people's furnaces up and running," Marino said.

Reach Megan Workman at megan.work...@wvgazette.com or 304-348-5113