Sistek: Western WA flooding could break all-time records as atmospheric river unleashes historic rainfall
Dec 11, 2025, 11:03 AM | Updated: 4:48 pm
The video above was filmed by Todd Elvig with STSPN.com
Meteorologist Scott Sistek said some rivers are approaching their worst-ever levels, with 12 waterways reaching “major” flood stage across the region.
Western Washington is experiencing one of its most severe flood events in decades after a powerful atmospheric river dumped record rainfall. The Skagit and Snohomish rivers are threatening to surpass historic crests, with meteorologists warning that some communities could see the worst flooding ever recorded.
There is, however, a small silver lining: forecast models have pulled back slightly from their most extreme predictions, and the worst of the rain has already passed.
“For some rivers, we’re talking about breaking all-time records,” Scott Sistek, meteorologist and author of the Emerald City Weather Blog, told “Seattle’s Morning News” on KIRO Newsradio. “Think of 1990, think of 2021 up north. We’re matching, if not exceeding, some of those numbers.”
Sistek, who has been tracking the storm’s progression at EmeraldCityWeather.com, said the flooding ranks among the most significant weather events in recent memory.
“In some places this may be the worst ever; in other places it may be a top-three or top-five event,” Sistek said. “We definitely haven’t seen something this intense in a while.”
Skagit and Snohomish rivers approach record crests
The Skagit River at Mount Vernon remains the primary concern, with forecasts showing the river cresting approximately two feet above its record flood stage. That is serious, but the news could have been worse. Earlier projections had the river running even higher.
“It was looking like four feet yesterday,” Sistek said.
Upstream at Concrete, the forecast has also improved. That gauge is now expected to crest right around its record flood stage rather than several feet above it.
The timing of the flooding varies by location. Concrete will see its peak on Thursday morning before beginning a slow decline, while Mount Vernon faces a longer wait.
“They are going to see the river slowly rise through today,” Sistek explained. “They are not expected to crest until tomorrow morning.”
The delay is a function of basic hydrology. Rain that falls in the Cascades has to collect into streams, feed into rivers, and then travel miles downstream before reaching lowland communities. For a large watershed like the Skagit, that journey from the mountains to Mount Vernon can take a full day or more.
Watching the Skagit River in the historic flood area… just outside #MountVernon – expected to crest at 42 feet tomorrow! @KIRONewsradio @Mynorthwest pic.twitter.com/ro4N0ydhPn
— Luke Duecy (@LukeKIRO) December 11, 2025
A dozen rivers in major flood stage across the region
The scope of the flooding extends well beyond the Skagit. Sistek counted 12 rivers reaching major flood stage throughout Western Washington, describing the situation as too widespread to fully catalog.
“The Snohomish and the Skagit are the two biggies,” he said. “And then the Skykomish, the Snoqualmie, and even the Puyallup have had some pretty decent problems.”
The Snohomish River is forecast to crest at its record flood stage, while the Snoqualmie approaches a top-three event in its recorded history. The National Weather Service (NWS) confirmed Thursday morning that the Snohomish River at Snohomish reached 33.57 feet, surpassing the previous record of 33.5 feet set in November 1990.
“Pretty much if you’re along a river, it’s doing something today,” Sistek said.
Storm shifted north, catching forecasters off guard
The atmospheric river did not behave exactly as meteorologists anticipated. Early in the week, forecasters expected the heaviest impacts to hit rivers in the southern part of the region, including the Cowlitz. Instead, the storm’s worst fury landed farther north.
“These things always have a mind of their own,” Sistek said. “The atmospheric river focused more of its wrath up north, so the Skagit, the Snohomish, and even the Snoqualmie delta saw the heaviest rain.”
The unpredictability is inherent to these systems.
“An atmospheric river is never locked in place,” Sistek said. “It moves up and down, and you have to go with the flow.”
Atmospheric river stretched nearly to Asia
The sheer volume of moisture fueling the flooding has been staggering. NWS reported that Western Washington absorbed nearly five trillion gallons of rain over the past week.
Sistek said the statistic reflects the extraordinary reach of the atmospheric river system.
“This stretched not just past Hawaii. It went almost all the way to Asia,” he said. “Think of all that warm tropical moisture making a beeline for the Northwest.”
Mountain areas bore the brunt of the onslaught, with 10-13 inches of rain falling during the storm. Warm temperatures meant the Cascades received virtually no snow, sending all that moisture downstream as runoff.
Sistek put those numbers in perspective: “That 10 inches would have been probably a hundred inches of snow had it all fallen as snow.”
Wind speeds compounded the rainfall totals.
“Gusts hitting 75-100 miles an hour up in the mountains at the ski resorts,” Sistek said. “Think of that wind slamming all that moisture into the mountains and wringing it out like a sponge.”
Relief expected by Saturday
Residents can expect conditions to gradually improve over the coming days. Sistek confirmed that the worst of the atmospheric river has passed, though lingering rain will continue Thursday.
“Rain will end from south to north today,” he said. “Tomorrow will have lingering showers here and there. Lighter showers, not a dry day, but not a super wet day.”
Saturday offers the best chance for a break.
“It doesn’t look like it’s going to rain much at all,” Sistek said. “We might actually get by mostly dry.”
He cautioned against long-term optimism, though. Light rain returns Sunday, and the extended forecast shows more wet weather ahead.
“Don’t ask about next week,” he said. “It looks like we go right back into the wet.”
The Christmas outlook remains unsettled, though Sistek sees one potential bright spot: cooler temperatures could finally bring snow to the Cascades rather than the rain that has plagued the mountains this week.
For ongoing forecasts and river observations, Sistek’s analysis is available at Emerald City Weather Blog.
Charlie Harger is the host of “Seattle’s Morning News” on KIRO Newsradio. You can read more of his stories and commentaries here. Follow Charlie on X and email him here.
