WISCONSIN RAPIDS, Wis. (AP) As residents across Wisconsin shovel away the remnants of the weekend snowstorm, one snow-removal expert is advising them to keep their roofs as snow-free as possible.

Most people think the threat from having snow piled on a roof is the weight issue, said Jerry Haasl, owner of snow-removal company Central Home Improvement in Wisconsin Rapids.

But the bigger threat is ice dams, which form on roof edges when heavy snowfall is combined with rain and long-term cold.

``A lot of people don't realize that is the big issue,'' he said.

As heat inside a home rises, it melts the first layers of snow on a roof, he said. Melted snow then runs to the edge of the roof and freezes, forming an ice dam that can cause water to collect.

The water can then leak into homes, causing structural damage that can cost thousands of dollars to replace, Haasl cautioned.

Homes in central Wisconsin are most susceptible right now because those regions were hardest hit by the weekend's storm, blamed for at least 22 deaths nationwide, including at least five in Wisconsin.

Wisconsin Rapids received a state-high 18.2 inches of snow from Saturday to Sunday, according to the National Weather Service. Lincoln, Marathon and Portage counties received between 14 and 16 inches.

Central Home Improvement has cleared about 30 roofs this winter, three times its seasonal average, Haasl said.

Homeowners with an older home, or one with a slightly sloped roof, should have snow removed right away, Haasl said. Homeowners can do the removal themselves but they should do it from the ground to avoid falling, he said.

``If they don't do it on their own, make sure they get somebody up there that is insured,'' Haasl advised.