Last updated:

Washington Landslides

On March 22, 2014, groundwater saturation triggered a landslide in Washington state, covering approximately one square mile. The Governor of Washington declared a State of Emergency on March 22, and a FEMA Emergency Declaration for the affected region was approved on March 24.

The area had experienced heavy rains throughout early spring. Communities affected include Oso, with a population of about 180, and Darrington, a town of approximately 1,350.

In a landslide, masses of rock, earth or debris move down a slope. Debris and mudflows are rivers of rock, earth, and other debris saturated with water. They develop when water rapidly accumulates in the ground, during heavy rainfall or rapid snowmelt, changing the earth into a flowing river of mud or “slurry.” They can flow rapidly, striking with little or no warning at avalanche speeds. They also can travel several miles from their source, growing in size as they pick up trees, boulders, cars and other materials, according to FEMA.

Geologist Dave Norman said the landslide was about 4,400 feet wide. In some places, the debris is 30 to 40 feet thick. Readings from the Pacific Northwest Seismic Network revealed that the hillside collapsed in two stages: The lower part of the slope gave way at 10:37 a.m. PT, triggering seismic activity that lasted two and a half minutes. This first slide destabilized the upper part of the slope, which collapsed four minutes later and set off a smaller seismic shock. Smaller landslides continued for days afterward.

During the mudslide, debris and sludge covered a portion of State Route 530, which connects the communities of Oso, Darrington, Arlington, and others in two counties. The Washington Department of Transportation reported that about 100,000 cubic yards of material covered SR 530. The road reopened on May 31, 2014.

The sludge and debris also blocked the flow of the Stillaguamish River, and permanently changed its path. The U.S. Army Corps of Engineers constructed a berm that allowed workers to pump river water out of a 260-acre area of the mudslide, in order to make it safe to continue searching for those missing, and crews to continue the next phase of recovery work.

What was the impact of this disaster?

FEMA reported 42 fatalities. One person is missing and 13 were injured. Thirty-nine homes were destroyed by the mudslide and flooding destroyed seven additional homes outside of the mudslide area. The Governor of Washington declared a State of Emergency on March 22, and a FEMA Emergency Declaration for the affected region was approved on March 24. President Barack Obama issued a major disaster declaration for the State of Washington, making federal funding available to people affected by the landslide. The president also visited the area on April 22.

The U.S. Army Corps of Engineers constructed a 3,000-foot berm to assist in recovery efforts.  The berm held back further water drainage, helped dry out areas for search teams to complete their work, alleviated blockage in the Stillaguamish River and addressed the closure of State Route 530 due to debris and sludge.

Facts & stats
  • Communities impacted included Oso, with a population of about 180, and Darrington, a town of about 1,350.
  • There were 42 confirmed fatalities, and 1 still missing.
  • 43 structures were affected (37 destroyed and 6 damaged).
  • Thirteen people were injured.
  • FEMA reported that 39 homes were destroyed with seven additional homes outside of the mudslide area destroyed by flooding.
  • The Governor of Washington declared a State of Emergency on March 22, and a FEMA Emergency Declaration for the affected region was approved on March 24, 2014.
  • About 100,000 cubic yards of material covered State Route 530 before it reopened in May 2014.
Philanthropic and government support

Our partner National VOAD suggests that the most effective way to assist relief efforts is by making cash contributions to humanitarian organizations that are conducting relief operations. This will ensure a well-coordinated and well-resourced response.

Our partner The Council on Foundations reported that a number of Northwest nonprofits and philanthropic organizations have begun responding with both emergency relief and longer-term assistance for the folks who have been injured and displaced by this tragedy, including:

  • The Greater Everett Community Foundation has opened an Emergency Needs Fund to provide assistance for the Oso and Darrington communities impacted by the recent, tragic mudslide. This fund will support immediate and longer term needs for these communities. Donations can be mailed to the Greater Everett Community Foundation, 2823 Rockefeller Ave, Everett WA 98201 or over the phone at 425-212-4056.
  • The Stanwood Camano Area Foundation is accepting credit card donations online on behalf of the Darrington Recreational & Education Foundation
  • The United Way of Snohomish County is also taking online donations for their relief fund.  To date, the United Way of Snohomish County has raised $2,133,547. Commitments and/or disbursements have been made to families, individuals, organizations, and public groups in the affected areas, helping with shelter, commuting costs, lost wages, trauma support services, and more.

NGO Response

  • The Washington VOAD has indicated that there are no unmet needs at this time and that most of the WA VOAD support right now is focused specifically on the response phase as well as on the emotional and spiritual care needs of survivors. We have also learned from the Corporation for National & Community Service that volunteers are discouraged from the search efforts. They request that people, instead, volunteer in the coming weeks and months as recovery begins.
  • The Red Cross is taking the lead in providing shelter and support to both the survivors and the rescue crews. The Red Cross responded immediately quickly opening shelters, handing out meals and snacks, activating Safe and Well to connect families who are still searching for loved ones and staffing shelters and resource centers with Mental Health volunteers to help them cope with the recent events. It mobilized two response vehicles and nearly 100 trained workers to provide support. Workers have served 3,800 meals and snacks, and handed out dozens of comfort kits. Because of the difficult nature of this event, local mental health volunteers who are caring for families who have lost loved ones and waiting for word on the missing. The Red Cross is working in close coordination with officials to determine how we can best help the community and support emergency workers over the coming days.
  • Catholic Community Services of Western Washington is now accepting donations that will be forwarded to Rev. Timothy J. Sauer, Pastor at St. John Vianney Church (Darrington) and Immaculate Conception Church (Arlington). These parishes are assisting people in the Oso community in a variety of ways, including helping to defray funeral costs for loved ones. Assistance will also be provided to those who have lost their homes and possessions.


See them all



Landslides are a movement of a mass of rock, debris or earth down a slope. Landslides are a type of ‘mass wasting,’ which denotes any down-slope movement of soil and rock under the direct influence of gravity.