Flood fears rising as atmospheric river of storms line up to hit Whatcom County
Weather forecasters and others are growing more concerned about the risk of flooding as a series of warm, wet and windy storms approach Whatcom County in a stream of precipitation called an atmospheric river.
After a pair of fairly typical fall storms were expected to dump rain in the lowlands and heavy snow in the mountains on Friday and Saturday, another series of moisture-laden storms are heading for Western Washington, starting Sunday night and lasting into Tuesday.
Those systems are warmer and will bring increasingly heavy rain to the lowlands and the North Cascades above 5,000 feet, according to the latest forecast from the National Weather Service in Seattle.
“With snow levels rising during this time and relatively warm rain falling on fresh snow, hydrologic impacts can be expected, especially with the continuous swath of moisture, this will make river flooding more likely along with snowmelt runoff in the mountains,” meteorologist Kayla Mazurkiewicz said online.
Total rainfall amount from the storms could be 4 inches in Bellingham through Tuesday — that’s about the average rainfall for the entire month of December. Rainfall in the mountains could reach double digits, on top of several feet of fresh snow.
What’s worrying forecasters and disaster-preparedness officials is the rain-on-snow scenario, where rain could cause rapid snowmelt that will engorge the Nooksack and cause flooding in the lowlands around Everson and farther downstream.
“Public Works crews are closely monitoring this weekend’s rainstorms and have been doing as much preventative maintenance as possible, including clearing catch basins and storm drains,” Public Works Department spokeswoman Torhil Ramsay told The Bellingham Herald.
”We look at a number of factors, including lake and river levels, and we don’t anticipate any major flooding. We do however caution drivers and pedestrians to obey any street closure signs, and not drive or walk into flooded areas,” Ramsay said.
Amy Cloud at the Whatcom County Sheriff’s Office Division of Emergency Management told The Herald that several county department are engaged in flood preparation.
“We’re posting information on our Whatcom Ready Facebook page, a shared resource with city of Bellingham’s Office of Emergency Management, and will be adding more links to information from local and state partners on the Whatcom Ready webpage,” Cloud said in an email.
Current estimates from the Northwest River Forecast Center show that the Nooksack River looks to crest around 16 feet in Ferndale on Wednesday. That’s below the flood stage of 18 feet, but above the “action stage” level when weather officials recommend making preparations for flooding.
Farther upstream at Nugents Corner, forecasts show the river cresting just below action stage of 145 feet.
“Confidence is high” for flooding across the state, however, the National Weather Service said in an emailed briefing late Thursday.
“The heaviest rainfall and the greatest risk of river flooding is expected Tuesday into Wednesday,” forecasters said.
