Officials with Washington and Clackamas counties are urging homeowners and business owners to make sure downspouts and catch basins are clear of snow and ice so water has someplace to go.

“The warmer rainy weather we are expecting, on top of the recent heavy snowfall, could present a threat for roof collapses, as well as localized street and basement flooding,” Scott Porter, Washington County Emergency Manager, said.

“Ice dams” may have formed in roof gutters and down spouts, causing water to back up through roofs and seep into homes and commercial buildings, causing damage that necessitates costly repairs. If it’s not cleared off roofs, snow acts as a sponge, absorbing any additional sleet and rain, adding stress to structures. Flat, commercial roofs are most susceptible if they are not draining properly.

The county is offering the following suggestions to minimize the risk of overstressing a building roof due to accumulated or drifting snow:

Be on the alert for large accumulating snow build-up or snowdrifts on your roof.

• If roof snow can be removed, do so with caution. Use plastic shovels or brooms rather than metal shovels. Try to avoid working from ladders as ladder rungs tend to ice up. Flat roofs can be shoveled clear, but only if it is determined that the roof is safe to stand upon. Exercise care when on the roof to avoid potentially dangerous falls.

• Flat roof drainage systems should be kept clear to minimize the risk of excess roof ponding in the event of subsequent heavy rainfall or melting.

• Large icicles can form on roof overhangs, but do not necessarily mean that ice damming is occurring. Icicles overhanging doorways and walkways can be dangerous and should be carefully removed.

Wilsonville public works officials said they are still working hard trying to mitigate localize flooding on area streets.

“We are making a point to check storm drains and basins around the city,” said Delora Kerber, Wilsonville public works director. “We are driving around different areas where there is a sag or a dip in the road to make sure things can flow.”

Kerber also warned drivers to be on the lookout for broken tire chains in the roadway.

“They can be dangerous, so we are urging people to be cautious as the melt occurs,” she said.

Kerber said she didn’t have statistics on how many hours crews spent trying to keep roadways passable, but was putting the numbers together.

“Anytime in the city you see the really dirty snow, that means we sanded there,” she said. “Our crews are going to be happy when they can get back to their winter maintenance schedule. They have been on 24-hours a day for several days now.”