Water that melts from snowy roofs doesn't always make it to the ground.

It can get trapped by ice dams, and many North Idahoans are dealing with these problematic formations right now.

"They're starting to roll in," said Lance Ragan, owner and president of Granite Enterprises Roofing in Rathdrum. "We've warned our staff."

Ice dams occur when thick ice forms on eaves and roof edges and prevents melting snow from draining. The water pools and works its way under shingles and roofing, causing damage to roofs, ceilings, walls and other areas. Damage and removal expenses vary with each situation, but can include paying crews up to $50 per hour per person, plus supplies and equipment costs.

"The repair at this juncture is fairly costly," Ragan said. "Damage can be more costly when it starts to come inside and ruin the paint or drywall."

Ice dams happen in any location that receives ice and snow. When warm air gets caught upstairs or in an attic, it causes the snow over those areas to melt and trickle off the roof. When that water can't roll off because of the ice dam, it will find its way in.

"It can be caused by the roofer on the ventilation end, but primarily it's because of poor construction or lack of insulation where there is heat loss," Ragan said. "It's one of the coldest winters that we've had, that's why some of the ice dams are occurring. The more heat that gets used as people turn up the thermostat when it's cold, the more they occur. It all goes together."

Mike Farrar, project manager for Lake City Roofing and Construction in Post Falls, said a good indicator that someone has an ice dam is bare spots on the roof where heat has escaped and melted the snow. Giant icicles are a good determination as well. Blocked rain gutters also contribute to the problem.

"The biggest thing we're finding is people not cleaning their gutters out for proper flow of water," Farrar said. "Keeping your roof clear of debris is important because you want the water to have somewhere to go."

Ragan said the best way to avoid ice dams is to check attics for added insulation in the summer time and be sure the cross-ventilation will push out warm air. If the dam already formed, he suggested using a snow rake to clear the snow from the perimeter and eaves to give the water a flow channel during upcoming warming trends.

He did not recommend using force to remove the dams.

"People think they can chip away at it. That's much harder than the average person thinks," he said. "That's like going to the lake and using a hatchet or a hammer to chip a hole in there."

Farrar said his company had already received at least 20 reports of ice dams by Tuesday afternoon.

"We're getting several calls. We're out in the field right now. I have guys taking care of them right now," he said. "It all depends on how the winters hit and the freeze and thaw. This year is an unusual year. There are a lot more this year than normal."

Both men said heat tape on eaves and gutters will somewhat help with the water flow while de-icers will assist in reducing the ice mass.

Farrar said he recommends ice dam removal be left to the pros.

"The only thing you can do is hire a pro to remove it," he said. "You don't want to get up there with a hammer or a pick. That can destroy the roof and then we'll have to replace it next year. You have to be careful."