At 3:30 p.m. on Wednesday, December 10th, residents of Sumas, Washington, nestled in the Nooksack River floodplain on the state’s northwest border, received a stark warning of encroaching floodwaters. The city’s flood alarm sounded with an ominous wail, a sound that reportedly reached as far north as Abbotsford, British Columbia. Heeding the alert, most residents swiftly gathered their children, pets, and essential belongings, seeking refuge in flood shelters, hotels, or the homes of nearby friends. The following morning, the sole access routes into and out of Sumas lay submerged beneath feet of frigid, silt-laden river water, inundating hundreds of homes and businesses and leaving a fine layer of mud on virtually every surface. Dozens of residents who had remained were dramatically rescued from their rooftops by a U.S. Coast Guard helicopter. By December 12th, as the waters began to recede, a visible high-water mark was evident throughout the town, marked by a tangled accumulation of trash, leaves, and debris clinging to chain-link fences, and muddy streaks adorning the sides of nearly every home and vehicle within the inundated zones.

Two successive atmospheric rivers unleashed their fury upon Washington’s west coast in early December, with some locations recording as much as 14 inches of rain within a 72-hour period at the height of the storms. Low-lying agricultural areas bore the brunt of the devastation, while the foothills of the Cascade Range and urban centers like Seattle, Everett, and Bellingham experienced less severe impacts. Now, the arduous process of recovery is underway. On December 12th, in the town of Nooksack, located a short distance from Sumas, I joined a contingent of volunteers to assist homeowners in the challenging task of cleanup. Donning thick work gloves, tall rubber boots, and waterproof jackets, we hauled waterlogged carpets and building materials to the street for collection. Other volunteers ventured into crawl spaces still submerged in standing water, diligently removing soaked insulation and muddied vapor barriers. Additional support came from the Whatcom Long Term Recovery Group, an organization established in the wake of similar devastating floods in north Whatcom County in 2021. Stationed at the Nooksack Valley Church, volunteers offered assistance in both English and Spanish, guiding residents through the complexities of insurance claims and state aid, while also providing crucial emotional support as flood victims returned to their devastated communities and confronted the daunting question of how to move forward. As of December 19th, nearly 800 families in Whatcom County had registered for assistance from the recovery group.

Atmospheric rivers, characterized as narrow bands of concentrated water vapor originating over the warm waters of the Pacific Ocean, are a regular feature of the West Coast’s weather patterns, delivering substantial precipitation. However, the recent series of storms proved exceptionally extensive, extending their reach as far south as central Oregon. Over 100,000 Washington residents faced mandatory evacuation orders as coastal rivers draining the Cascade Range reached their peak flows on December 11th and 12th. In Skagit County, approximately 60 miles north of Seattle, the communities of Concrete and Hamilton were particularly hard-hit. Bridget Moran, a fisheries biologist working in Skagit County who was actively involved in assisting residents with home cleanups, observed that the high-water mark in some Hamilton homes exceeded six feet. Further downstream, the Skagit River, surging at a record-breaking 37.7 feet, was prevented from inundating downtown Mount Vernon solely by the presence of a pre-existing floodwall.

Not all communities were as fortunate in their defenses. In the nearby city of Burlington, 55 homes and sections of the downtown core were submerged on December 12th, necessitating the evacuation of nearly 10,000 residents. In south King County, floodwaters breached a previously weakened levee on the Lower Green River near the town of Pacific in the early morning of December 16th. This event prompted officials to issue evacuation orders for 2,100 residents in the surrounding area. Ultimately, the floodwaters impacted approximately 220 homes and around 800 individuals. In Snohomish County, south of Skagit, a 33-year-old man lost his life after attempting to drive through a closed road and being swept away by floodwaters, marking the first and, to date, only confirmed fatality attributed to the flooding.

Communities situated at higher altitudes in the East Cascades, such as Naches, Leavenworth, and Methow, typically experience colder and drier conditions compared to areas west of the mountain range. However, the nature of the recent precipitation, with the majority arriving as rain rather than snow—even at the highest elevations of the Cascades—led to catastrophic flooding, widespread power outages, and significant mudslides in these regions as well. In Stehekin, near the burn scar of the 2024 Pioneer Fire, residents and businesses suffered considerable damage from landslides and post-fire debris flows in recently burned areas, where scorched soils and vegetation are inherently more susceptible to destabilization. Further south along the Cascade crest, Stevens Pass sustained such extensive damage that its closure is anticipated to last for several months, while multiple landslides rendered eastbound Interstate 90, the primary transportation artery through the Cascades, impassable.

Washington was subsequently impacted by a third, albeit colder, atmospheric river during the week of December 15th. This precipitation fell upon watersheds already saturated from the preceding week’s rainfall, triggering further flooding, though on a less severe scale. However, the accompanying high winds proved more destructive than the water, leaving an estimated 380,000 people across the state without power due to downed lines and damaged infrastructure.

The USDA Northwest Climate Hub highlights the escalating threat posed by the combination of increasingly hazardous atmospheric rivers and the overarching effects of climate change. A warmer atmosphere possesses a greater capacity to hold moisture, while a warming Pacific Ocean serves as a vast reservoir, supplying this moisture. Consequently, the duration and intensity of these atmospheric river events are projected to increase. Guillaume Mauger, the Washington State Climatologist, explained that when these factors converge, "we’d expect the storms to be more intense." According to Mauger, the heightened danger of this particular series of atmospheric rivers stemmed not only from their individual strength but also from their rapid succession.

Mauger emphasized that researchers are still gathering definitive data to fully comprehend the precise influence of climate change on this specific storm event. However, he noted that the unseasonably warm temperatures and the significant shift towards rainfall instead of snowfall, even at higher elevations, likely indicate the impact of climate change. "Atmospheric rivers are warm in general," he stated, "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 throughout Washington are now entering the recovery phase, as residents work to salvage belongings and remove damaged materials from their homes while simultaneously seeking financial assistance. Washington Governor Bob Ferguson has allocated $3.5 million in emergency funding to aid flood victims and has proposed a supplemental budget that includes $55 million designated for home repair and recovery efforts. President Donald Trump has approved Governor Ferguson’s request for federal disaster assistance, which enables the Federal Emergency Management Agency (FEMA) to provide support to communities and local governments, though it does not directly unlock federal funding for individual victims.

Several factors are likely to complicate the recovery process in many of the affected areas, including a high proportion of renters, the prevalence of manufactured homes, and a widespread lack of flood insurance, according to a report by the Urban Institute. Data indicates that only about a quarter of homes situated within the 100-year floodplain in Whatcom, Skagit, and Snohomish counties are covered by the National Flood Insurance Program, a federally administered policy designed to offer insurance to individuals who might otherwise face difficulties obtaining coverage due to their low-lying locations.

Shortly after the floodwaters receded on December 12th, I assisted another volunteer in removing ornaments and lights from a family’s Christmas tree in Nooksack. The lower branches of the tree were coated in mud, and the floor around it was thick with silt. Elsewhere, other volunteers worked quietly, carrying out couches and children’s toys that still dripped with river water. Later, standing in the driveway, I observed volunteers systematically removing sodden items from every home on the block—a task that would be replicated in thousands of homes across the state in the weeks and months ahead. The sheer scale of the devastation was overwhelming, yet there was little time for reflection: pressing tasks remained, from removing damaged trim and ripping out flooring to completing essential paperwork, rebuilding lives, and ultimately, renewing communities.