National Weather Service meteorologists are warning of possible flooding from potentially heavy rainfall expected Monday night through Wednesday, and county officials are setting load limits on some roads to guard against damage as the ground thaws.
A flood watch was issued at 3:23 p.m. Monday, warning of the potential for flooding in several Northwest Washington counties, including Whatcom County, where the Nooksack River is of the most concern. Meteorologists say the Nooksack is likely to hit flood stage Tuesday night or Wednesday.
The U.S. Geological Survey monitors water levels in rivers and streams. For updated flooding information information, go to wa.water.usgs.gov and look under “Latest river conditions.”
Following several weeks of cold, dry weather across Northwest Washington – daytime temperatures hovered around freezing and little precipitation fell – a warm, wet storm system is moving in from the west. Heavy rain is expected at higher elevations of the North Cascades, as much as 4 to 7 inches, meteorologist Johnny Burg said.
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“In the lowlands, it’s going to be a little bit less,” Burg said. “But in the mountains, it’s going to run right into the rivers.”
Western Washington rivers are running low, but heavy rain could cause them to rise quickly and flooding could begin Tuesday or Wednesday, the weather service said in an online statement posted Sunday morning.
For lowland Whatcom County, Monday brings a 50 percent chance of rain with temperatures in the mid-40s. Forecasters said rain is likely Monday night, with overnight totals of a half-inch or more in the lowlands.
Rain also is likely Tuesday, with another half-inch and highs approaching 50 degrees. Rain also is forecast to continue Wednesday.
Burg said lowland Whatcom County could expect as much as 3 inches of rain from Monday night into Wednesday.
A chance of showers will continue Thursday through Saturday with highs in the mid-40s.
With the warmer weather, the ground will start thawing, possibly damaging some roads as water is trapped between the road surface and the frozen ground, causing the road to float on a layer of water.
Heavy loads can break through the pavement, said Remy McConnell, coordinator of engineering services for the Whatcom County Public Works Department.
“It starts tearing up the road,” McConnell said.
Emergency load restrictions affect only heavy loads and not passenger cars and buses, she said. For a list of roads that are built to all-weather standards and aren’t affected, go online to whatcomcounty.us.