Coastal Hazards in Washington State

Dwellers on Washington’s seismically active, highly exposed shores face a daunting range of natural and human-induced hazards. Some are continual and inexorable, such as climate-driven sea level rise. Some are commonplace phenomena, such as winter storms, seasonal flooding, and bluff erosion. And some are rare but cataclysmic events: major earthquakes and tsunamis.

Photo: John Fowler

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    Off Washington’s ocean coast lies a subduction zone where one continental plate, the Pacific, is slowly pushing under another, the North American Plate. Pressure builds up along this faultline until it releases with devastating force, in the form of earthquakes that may top 9 on the moment magnitude scale. The evidence suggests our region is due for another.The tsumani generated by a large quake along this Cascadia Subduction Zone could reach communities on Washington’s ocean coast within 20 minutes and larger communities on the Strait of Juan de Fuca in less than an hour. Nevertheless, many jurisdictions are unprepared for such a catastrophe. Much more could be done to build resilience, from evacuation planning to relocating critical infrastructure out of the inundation zone.

    Meanwhile, winter storms pound the coast mercilessly, with winds sometimes reaching hurricane-level force. Since the days of early settlement, and occasionally since, rising waves and eroding beaches claimed coastal homes and other structures. At the south end of the Olympic Peninsula, the sprawling Moclips Beach Hotel, together with many homes, was shattered by storms in 1911 and 1913.

    Today, as global climate change causes Arctic ice to melt and warming seawater to expand, rising sea levels throw a new threat at coastal communities. Many of them, including native tribal communities, were built close to shore, at the mouths of rivers, where fish and fresh water were plentiful. Now those estuarine settlements are particularly vulnerable to sea rise and seasonal flooding. One, the Quileute Tribe on the Olympic Coast, is making plans to move upland because of their village’s acute exposure to tsunamis. The Quileutes have already secured land from the Olympic National Park to relocate their school, which stands just one foot above current sea level.

    Washington Sea Grant’s (WSG) coastal-resilience specialists are at the forefront of efforts to understand, anticipate, and mitigate coastal hazards.


Community Engagement

Whether it’s providing practical demonstrations of the implications of sea level rise or preparing communities and governments for flooding, erosion and other challenges associated with climate change, WSG staff are at the forefront of helping Washingtonians understand and adapt to our changing climate.

  • WSG funded and collaborated with scientists to study the coastal influence of the removal of the Elwha River Dam. To visit the site of the largest dam removal in the world, and one of the largest ecological restoration projects ever attempted, follow our self-guided field trip of the Elwha River Restoration Tour.
  • Tacoma partnered with WSG on the NOAA-funded “Washington Coastal Resilience Project” as a pilot community, testing methods to incorporate technical guidance for coastal hazards and climate change into community plans. To experience this work, walk along the waterfront with directions from the Tacoma Working Waterfront and Tideflats self-guided field trip.
  • WSG’s Marine Spatial Planning Specialist Bridget Trosin coordinates the Washington King Tides program which invites citizens to “snap the shore and see the future” and share their photos of the twice-yearly extreme tides — “king tides” — online, opening a window for coastal residents and decision makers onto how changing climate and rising seas will affect their communities.
  • WSG, working with the Washington Department of Ecology (WDOE), is building the statewide Washington Coastal Hazards Resilience Network, which will inform and coordinate state, federal, and local planning efforts.
  • WSG and WDOE also coordinate the Shoreline and Coastal Planners Group, which has focused initially on anticipating and planning for sea level rise.
  • WSG developed a course on Sea Level Rise Adaptation to help communities adapt their infrastructure and zoning and building codes; this course is offered through the Department of Ecology’s Coastal Training Program.
  • WSG is conducting a course on Coastal Flood Risk Reduction offered through the National Disaster Preparedness Center in Hawai’i. Communities seeking to reduce their potential flood losses may request a presentation of this course at a venue of choice, tailored to local conditions.
  • Ian Miller, WSG’s Olympic Peninsula-based Coastal Hazards Specialist, led the development of a comprehensive climate change assessment for the Olympic National Marine Sanctuary, the first such assessment in the national marine sanctuary system. He also helped the Jamestown S’Klallam Tribe draft its Climate Vulnerability Assessment and Adaptation Plan.

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