At 3:30 p.m. on Wednesday, December 10, residents of Sumas, Washington, a community situated in the Nooksack River floodplain near the state’s northwest border, received an urgent warning of rapidly rising floodwaters. The city’s flood alarm blared with an unsettling wail that echoed as far north as Abbotsford, British Columbia, prompting most residents to heed the alert. They quickly gathered their children, pets, and essential belongings, seeking refuge in flood shelters, hotels, or the homes of friends and neighbors. By the following morning, all routes in and out of Sumas were submerged, leaving the town and its surrounding areas inundated by several feet of frigid, sediment-laden river water. Hundreds of homes and businesses suffered damage, and a thin layer of silt coated nearly every surface. Dozens of individuals who had not evacuated were airlifted from their rooftops by a U.S. Coast Guard helicopter. As the waters finally began to recede on December 12, the devastating high-water mark was starkly visible, marked by accumulated trash, leaves, and debris clinging to chain-link fences and muddy streaks adorning the sides of nearly every home and vehicle within the flood zone.

The Pacific Northwest experienced a relentless onslaught of two back-to-back atmospheric rivers in early December, with some locations recording as much as 14 inches of rainfall within a 72-hour period at the storms’ peak intensity. Low-lying agricultural regions bore the brunt of the inundation, while the foothills of the Cascade Range and urban centers like Seattle, Everett, and Bellingham experienced less severe impacts. The arduous process of recovery is now underway. On December 12, in the town of Nooksack, situated just a short distance from Sumas, I joined a team of volunteers donning thick work gloves, high rubber boots, and waterproof jackets to assist homeowners grappling with the daunting task of cleanup. We hauled waterlogged carpets and building materials to the curb for collection, while other volunteers ventured into crawl spaces still submerged in standing water, diligently removing soaked insulation and muddy vapor barriers. Additional volunteers, affiliated with the Whatcom Long Term Recovery Group—an organization established in the wake of similar devastating floods in north Whatcom County in 2021—were stationed at the Nooksack Valley Church. There, they provided assistance to residents in both English and Spanish, guiding them through insurance claims and state aid applications, and offering crucial emotional support as flood victims returned to their devastated community and faced the daunting question of "what next." As of December 19, nearly 800 families in Whatcom County had formally requested assistance from the recovery group.

Atmospheric rivers, defined as narrow bands of concentrated water vapor originating over the warm waters of the Pacific Ocean, are a regular feature along the West Coast, delivering significant precipitation. However, this particular series of storms was unusually extensive, extending its reach as far south as central Oregon. Over 100,000 Washington residents were subject to evacuation orders as coastal rivers draining the Cascade Range reached their peak flows on December 11 and 12. In Skagit County, approximately sixty 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 cleanouts, observed that in some Hamilton homes, the high-water mark had reached over six feet. Further downstream, the Skagit River, flowing at a record-breaking 37.7 feet, was prevented from breaching the downtown area of Mount Vernon only by the presence of a protective floodwall.

Not all communities were as fortunate. In the nearby city of Burlington, 55 homes and sections of the downtown core were inundated on December 12, necessitating the evacuation of the town’s nearly 10,000 residents. In south King County, floodwaters breached an already compromised levee on the Lower Green River near the town of Pacific in the early morning of December 16, triggering evacuation orders for 2,100 residents from the area. Ultimately, the floodwaters affected approximately 220 homes and around 800 individuals. In Snohomish County, south of Skagit County, a 33-year-old man lost his life after attempting to drive on 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 Cascades. However, the nature of this event, with the majority of precipitation 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, an area 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 more susceptible to destabilization. Further south along the Cascade crest, Stevens Pass sustained such severe damage that its closure is expected to last for months, while multiple landslides rendered eastbound Interstate 90, the primary route through the Cascades, impassable. Washington experienced a third, albeit slightly colder, atmospheric river during the week of December 15. This precipitation fell on watersheds already saturated from the preceding week’s rainfall, causing further flooding, though on a less severe scale. However, the accompanying high winds proved to be more destructive than the water, leading to power outages for approximately 380,000 people across the state.

The USDA Northwest Climate Hub highlights the confluence of increasingly hazardous atmospheric rivers and the broader impacts of climate change. A warmer atmosphere possesses a greater capacity to hold moisture, while a warming Pacific Ocean serves as a more abundant source of this moisture. Consequently, the duration and intensity of these atmospheric river events are escalating. Guillaume Mauger, the Washington State Climatologist, explained that when these factors align, "we’d expect the storms to be more intense." According to Mauger, the heightened danger posed by this series of atmospheric rivers stemmed not only from their individual strength but also from their rapid succession. Mauger cautioned that researchers still require more definitive data to fully comprehend the precise influence of climate change on this specific storm event. Nevertheless, he noted that the unseasonably warm temperatures and the shift from snow to rain as the dominant form of precipitation, even at higher elevations, likely indicated the effects 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 across Washington are now transitioning into the recovery phase, with residents engaged in the painstaking process of salvaging belongings and removing waterlogged materials from their homes, while simultaneously seeking financial assistance. Washington Governor Bob Ferguson has allocated $3.5 million in emergency funding to support 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 aid to communities and local governments, although it does not directly unlock federal funding for individual victims. A report from the Urban Institute identifies several factors that are likely to complicate recovery in many of the affected areas. These include a high proportion of renters, a prevalence of manufactured homes, and a significant lack of flood insurance. The report indicates that only about a quarter of homes situated within the 100-year floodplain in Whatcom, Skagit, and Snohomish counties carry National Flood Insurance Program policies, which are federally administered plans designed to provide coverage for individuals who might otherwise struggle to obtain insurance due to their low-lying locations.

Shortly after the floodwaters receded on December 12, I worked alongside another volunteer to carefully remove ornaments and lights from a family’s Christmas tree in Nooksack. The tree’s lower branches were coated in mud, and the floor around it was thick with silt. Elsewhere, other volunteers worked quietly, methodically carrying out couches and children’s toys still dripping with river water. Later, standing in the driveway, I observed volunteers diligently hauling wet debris from every home on the block—a task that would be replicated in thousands of residences across the state in the weeks and months ahead. The sheer scale of the devastation was overwhelming, yet there was little time for contemplation; the immediate needs were pressing: the removal of trim, the tearing out of flooring, the completion of paperwork, the rebuilding of lives, and ultimately, the renewal of communities.