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Emergency Management

Prepare Respond Mitigate

King County Emergency Management
3511 NE Second St.
Renton, WA 98056
Main Phone: 206-296-3830
Toll Free: 800-523-5044
Fax: 206-205-4056

Enhanced 9-1-1 Program
Seattle, WA
E-911 program office

Regional Hazard Mitigation Plan (RHMP)

King County is committed to creating and sustaining communities that are more resilient to disasters. To fulfill this pledge, King County Office of Emergency Management (KCOEM) has recently updated the Regional Hazard Mitigation Plan (RHMP) in partnership with cities and special purpose districts throughout the County. Federal rules require this plan be updated every five years.

Photo: RHMP groupRepresentatives from King County and 54 different cities, schools, fire districts, hospitals and utility districts worked in partnership with KCOEM and Tetra Tech Incorporated - the contractor leading the hazard assessment and plan development. Decisions regarding plan elements, such as specific hazards to include, were made by a steering committee whose members include representatives from government, private business, non-profits, the public, and academia. 

In 2015, the final updated plan was approved by Washington State EMD and FEMA. King County and most partnering jurisdictions have formally adopted their plans. See the list of participating jurisdictions.

The RHMP is divided into seven sections:

Frequently Asked Questions

Question:  What is hazard mitigation and what is a Hazard Mitigation Plan (HMP)?  

Answer:  Hazard mitigation is defined as any sustained action taken to permanently eliminate or reduce long-term risks to human life and property from natural hazards. A Hazard Mitigation Plan is prepared by local governments in response to the Disaster Mitigation Act of 2000 (Public Law 106-390). These plans allow access to federal funding afforded under the Robert T. Stafford Act. These plans meet statutory requirements that include:
  • Organizing resources
  • Assessing risk
  • Engaging the public
  • Identifying goals and objectives
  • Identifying actions
  • Developing plan maintenance and implementation strategies
The foundation of any mitigation plan is a risk assessment that looks at natural hazards of concern within a planning area. The principle objective of a mitigation plan is an action plan that identifies and prioritizes initiatives that are sustainable, cost-effective, and will avoid future impacts and losses to the hazards that may affect the jurisdiction.

Question:  Why do counties do HMPs?

Answer:  The Disaster Mitigation Act of 2000 requires states and local jurisdictions to prepare and submit a hazard mitigation plan to the US Federal Emergency Management Agency (FEMA). Without an approved plan in place, the jurisdiction is out of compliance with the Act, thereby limiting eligibility for post-disaster mitigation grant funding available under the Robert T. Stafford Act. This funding is typically used for hazard mitigation and disaster recovery projects/programs. State plans are required to be updated every three years, and local jurisdictional plans must be updated every five years.

Question:  What should a jurisdiction do with the results of a HMP?

Answer:  Local governments should strive to implement the plan based on the priorities established through the planning process.

Question:  What natural hazards are assessed in a HMP?

Answer:  Local plans must be consistent with the State Hazard Mitigation Plan. The State identifies the minimum number of hazards of concern to be addressed by each local plan. For our region this plan covers avalanche, dam failure, earthquake, flood, landslide, severe weather, severe winter weather, tsunami, volcano and wildfire. While not an explicit requirement of the Disaster Mitigation Act, some jurisdictions also seek to include technological and terrorism risk in their risk planning program to evaluate such. 

Question:  How is the 2014 HMP plan different from previous plans? What’s new?

Answer:  The King County Office of Emergency Management used the current update process to make significant changes to the format and content of the regional plan. The plan was re-packaged to better support a larger partnership and to establish a plan maintenance and implementation protocol that clearly defines the King County Office of Emergency Management’s commitment to the plan’s ongoing success:
  • The planning partnership was increased to 54 planning partners including King County, cities, school districts, fire districts, utilities, hospitals and more. 

  • The plan was developed in two volumes. Volume 1 contains all required elements that apply to the entire planning area; Volume 2 contains elements that are jurisdiction-specific.
  • A comprehensive risk assessment is included for 10 hazards of concern, and an overview is provided for other hazards of interest.

  • The risk assessments made use of FEMA’s Hazus-MH risk assessment software.

  • A risk-ranking methodology was implemented that quantifies the impacts of each hazard so that each can be compared to the others.

  • A new methodology was implemented for prioritizing actions. 

  • A plan maintenance strategy is presented that includes a protocol and tools to support annual progress reporting, as well as a protocol for grant coordination. 

  • A prescribed linkage procedure will allow for future expansion of the partnership outside of the five-year update window.

  • A suite of tools and templates is provided to promote consistency of all future updates to the plan.

Questions about landslide risk in King County

The recent tragic loss of life due to a massive landslide on the Stillaguamish River prompted King County to review the County’s landslide risk and landslide preparedness. Although landslides are included in the risk assessment of the Regional Hazard Mitigation Plan, an additional effort is underway to update landslide hazard mapping within the county. The information garnered by this effort will be included in an amendment to the Regional Hazard Mitigation Plan.

Question:  Are landslides a risk in King County?

Answer:  Yes. Several landslides occur in King County every year. Slides can occur at any time, although most occur during the rainy season. Slides occur in urban and rural areas throughout the County; however, the shorelines of Puget Sound are particularly vulnerable to slide events.

Question:  How are landslide risks assessed?

Answer:  Three sources of data were used to approximate the extent and location of landslide hazard areas. Landslide location data was obtained from the Washington Department of Natural Resources and a landslide hazard data-set was obtained from King County Department of Natural Resources and Parks (DNRP). In addition, a data-set of potential landslide hazard areas was created using surface geology and a digital elevation model based on LiDAR data provided by King County DNRP. The combined three data sources were used to identify the extent and location of the landslide hazard areas. It should be noted that this level of detail is considered “awareness zone mapping” and is not considered to be suitable for use in a regulatory context. 

Risk is calculated by multiplying probability times impact on people, property, economy and environment, by identifying the geographic boundaries or location of the hazard, and intersecting the hazard area with an inventory of structures or critical facilities to determine exposure. For some hazards, such as flooding, we have models that can take the next step and estimate vulnerability. But those models do not exist for landslides, so landslide risk assessment is considered a qualitative process.

Question:  If you use new mapping technology – such as LiDAR – to update the map, is there a potential that the number of properties in hazardous landslide areas could increase?

Answer:  That’s a possibility. However, there is also the possibility that with the greater precision provided by modern technology, the size of the areas considered a high risk for landslides could decrease. We simply won’t know until the mapping project is complete. 

Question: Why hasn't King County updated its landslide hazard area in nearly 25 years?

Answer: The maps we created in the early 1990's still have value – geological conditions don’t change that rapidly. Of course, given the tragedy that occurred in Snohomish County, we want to ensure that we take advantage of current technology to minimize the risk in King County. 

Question:  How long would it take to update the maps for hazardous landslide areas?

Answer: Depending on how much detail we want the maps to show, it would likely take between one and three years.

Question:  Assuming you get updated maps, how do you ensure that prospective property owners are made aware that their property is now considered to be at greater risk from landslides?

Answer: We've always made maps of hazardous areas public, though the Snohomish County landslide obviously makes people more aware of these maps. If updated maps show landslide risks, we will consider  public outreach to inform not only those who are considering purchasing property but longtime residents as well. 

Question:  How can a community prepare for landslides and mitigate the risk? 

Answer:  Communities have a variety of ways to mitigate areas of high landslide risk.  For instance, a community may choose to revise its zoning code or ordinances to prevent building in certain areas of high-risk. They may also seek to use available post-disaster grant funding or other financial resources to conduct buyouts of properties located in high risk areas and convert these properties to permanent open space. (“Buy-out” means using federal and local money to buy homes in high risk areas and help families and citizens to relocate to less hazardous areas.) Communities may also wish to provide information through publications and/or workshops to inform citizens about best practices to help limit landslide occurrence and impacts. 

Don't see your answer here? Questions, comments or concerns can be sent to

 Hazard maps
Public presentations

Steering committee minutes