AT 3:30 P.M. ON WEDNESDAY, DEC. 10, the residents of Sumas, Washington — in the Nooksack River floodplain on the state’s northwest border — learned of the rising floodwaters. The city’s flood alarm had gone off with an unnerving wail that was heard as far north as Abbotsford, British Columbia. Most residents heeded the warning, grabbing their children, pets and important belongings and driving to flood shelters, hotels or the homes of nearby friends.
The next morning, the only roads in and out of Sumas were underwater. The town and its surroundings were inundated by multiple feet of frigid, dirt-laden river water that damaged hundreds of homes and businesses and left a thin layer of silt on nearly every surface. Dozens of residents who hadn’t evacuated were rescued from their roofs by a U.S. Coast Guard helicopter. When waters receded on Dec. 12, the high-water line was visible everywhere — marked by all the trash, leaves and debris stuck to chain-link fences and the muddy stripes left along the sides of nearly every home and vehicle in the flood zone.
Two back-to-back atmospheric rivers battered Washington’s west coast in early December, with some places receiving up to 14 inches of rain over a 72-hour period at the storms’ peak. Low-lying agricultural zones were the most heavily impacted, while the foothills of the Cascade Range, as well as urban areas like Seattle, Everett and Bellingham, were less affected.
Now begins the long and difficult recovery process. On Dec. 12 in the town of Nooksack — just down the road from Sumas — I donned thick work gloves, high rubber boots and a waterproof jacket, joining volunteers to assist homeowners with the soggy effort of cleanup. We carried waterlogged carpets and building materials out to the street for pickup, while others ventured into crawlspaces still inundated by standing water, pulling out soaked insulation and muddied vapor shields. Additional volunteers with the Whatcom Long Term Recovery Group — developed in the aftermath of north Whatcom County’s similarly devastating flooding in 2021 — were stationed at the Nooksack Valley Church, assisting residents in both English and Spanish with insurance claims and state assistance and providing emotional support for the flood victims as they re-entered their devastated community and wondered what to do next. As of Dec. 19, almost 800 families in Whatcom County had requested help from the recovery group.
ATMOSPHERIC RIVERS — NARROW BANDS OF concentrated water vapor that originate over the warm waters of the Pacific Ocean — regularly wallop the West Coast with precipitation. But this series of storms was more expansive than usual, dumping rain as far south as central Oregon. Over 100,000 Washington residents faced evacuation orders as coastal rivers draining the Cascade Range reached peak flows on Dec. 11 and 12. Sixty miles north of Seattle in Skagit County, the communities of Concrete and Hamilton were particularly hard hit; Bridget Moran, a fisheries biologist who works in Skagit County and was helping residents clean out their homes, noted that the high-water mark was over 6 feet high in some of the Hamilton homes. Farther downstream, the Skagit River, flowing at a record-breaking 37.7 feet, was only kept out of downtown Mount Vernon by the presence of a floodwall.
Not all communities were as lucky. In nearby Burlington, 55 homes and parts of downtown were inundated on Dec. 12, forcing the evacuation of the town’s nearly 10,000 residents. In south King County, floodwaters breached an already-weakened levee on the Lower Green River near the town of Pacific in the early morning of Dec. 16, prompting officials to evacuate 2,100 residents from the area. The floodwaters ultimately impacted around 220 homes and around 800 residents. In Snohomish County, south of Skagit, a 33-year-old man attempted to drive on a closed road and was swept away by floodwaters, marking the first and only confirmed death attributed to the flooding so far.
Higher-altitude East Cascade communities like Naches, Leavenworth and Methow generally experience colder and drier conditions than communities on the west side of the Cascades. But because the majority of precipitation arrived as rain rather than snow — even in the highest reaches of the Cascades — these areas also experienced catastrophic flooding, power outages and mudslides. In Stehekin, near the 2024 Pioneer Fire burn scar, residents and businesses sustained significant damage from landslides and post-fire debris flows in recently burned areas, where scorched soils and vegetation are more easily destabilized. Farther south on the Cascade crest, Stevens Pass was so badly damaged that it’s expected to be closed for months, while multiple landslides ripped across eastbound I-90, the main thoroughfare through the Cascades.
Washington was hit with a third, slightly colder atmospheric river during the week of Dec. 15. The precipitation, which fell on watersheds already inundated by last week’s rain, caused yet more flooding, though not as serious. But the wind proved ultimately more destructive than water, with some 380,000 people across the state losing power.
“If this event had happened in 1950, the snowline wouldn’t have been quite so high.”
THE USDA NORTHWEST CLIMATE HUB POINTS TO the combination of increasingly hazardous atmospheric rivers and climate change, noting that a warmer atmosphere can hold more water, while the warming Pacific Ocean provides more moisture. This means that the duration and strength of these atmospheric river events are increasing. Guillaume Mauger, Washington state climatologist, said that when these factors come together, “we’d expect the storms to be more intense.” According to Mauger, what made this series of atmospheric rivers so dangerous wasn’t just their individual intensity, but their quick succession.
Mauger was quick to point out that researchers still lack the hard data to understand precisely how climate change may have impacted this specific series of storms. But he noted that the unseasonably warm temperatures and the fact that more precipitation is falling as rain rather than snow, were likely an indication of climate change’s influence.
“Atmospheric rivers are warm in general,” he said. “But if this event had happened in 1950, the snowline wouldn’t have been quite so high. That’s the big effect: that it’s just less snow and more rain.”
COMMUNITIES ACROSS WASHINGTON ARE NOW ENTERING the recovery phase, as residents remove belongings and wet materials from their homes and seek financial assistance. Washington Gov. Bob Ferguson, D, is digging into $3.5 million in emergency funding to help flood victims and has proposed a supplemental budget that contains $55 million earmarked for home repair and recovery. President Donald Trump approved Ferguson’s request for federal disaster assistance, which allows FEMA, the Federal Emergency Management Agency, to assist communities and local governments, although it does not unlock federal funding for victims.
Certain factors are likely to make recovery more difficult in many of the impacted areas, including a high level of renters, the prevalence of manufactured homes and a lack of flood insurance, according to a report from the Urban Institute. Only around a quarter of homes located in the 100-year floodplain in Whatcom, Skagit and Snohomish counties have National Flood Insurance Program flood insurance, federally administered policies available to people who otherwise might not be able to obtain insurance due to their low-lying locations.
Just after floodwaters had receded on Dec. 12, I worked with another volunteer to remove ornaments and lights from a family’s Christmas tree in Nooksack — the tree’s lower branches covered in mud, the floor around it thick with silt. Others worked quietly around us, carrying out couches and children’s toys still dripping with river water.
Later, standing in the driveway, I watched as volunteers lugged wet items out of every home on the block — a process that would be repeated in thousands of homes across the state in the coming weeks and months. The scale of the devastation was overwhelming, but there was little time to think about it: There was still so much to do, all that trim to remove, flooring to rip out, paperwork to complete, lives to rebuild and, eventually, communities to renew.
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