Whatcom flood fears increase as heavy rain follows mountain snowfall

Flooding remains a possibility in Whatcom County as a pair of wet and windy storms are poised to dump heavy rain on fresh snowfall in the mountains — the same scenario that caused devastating floods in 2020 and 2021.

“An atmospheric river will impact the region through Tuesday with periods of heavy rain and an increased risk of river flooding,” National Weather Service meteorologist Dana Felton said in the Seattle area’s online forecast.

Many Western Washington rivers will reach flood stage late Monday night or Tuesday, and a flood watch was issued.

Flooding models show the Nooksack River is expected to crest below flood stage near Nugents Corner, according to the Northwest River Forecast Center.

But there’s more uncertainty for Ferndale, where the river was expected to crest Wednesday right at flood stage of 18 feet.

Severe flooding was expected in Mount Vernon, where the Skagit River was expected to be flowing well above major flood stage.

In addition, winds of 30 to 40 mph with gusts up to 50 mph were expected Monday afternoon and evening, according to a wind advisory for Bellingham and Western Whatcom County.

A gale warning was issued for adjacent waters.

Daytime temperatures were forecast in the upper 50s across the lowlands as the storms sweep north from the tropical Pacific.

More rain was predicted Tuesday in a deluge of stormy weather that could drop a total of 4 inches of rain in the Bellingham area — that’s almost all the rain expected in a typical month of December.

Two feet or more of snow fell in the Mount Baker wilderness after a pair of weekend storms, and much of that snow could melt, filling the rivers and streams coming out of the North Cascades.

Avalanche danger was high across the mountains of Western Washington, according to the Northwest Avalanche Center.

Backcountry enthusiasts reported the “whump!” sounds of cracking and tumbling snow on the Northwest Avalanche Center’s website over the weekend.

Further, the waterlogged ground leaves a higher potential for landslides, according to a “special weather statement” issued Monday afternoon by the National Weather Service.

“Heavy rainfall of 2.5 to 5 inches is expected today through Tuesday night. This amount of rain will put extra pressure on soil instability, leading to an increased threat of landslides and debris flows,” the statement said.