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King County Office of Emergency Management
3511 NE 2nd Street
Renton, WA 98056
Main Phone: 206-296-3830
Toll Free: 800-523-5044
Fax: 206-205-4056
ecc.kc@kingcounty.gov

Enhanced 911 Program
Seattle, WA
206-296-3910
E-911 program office

Avalanches

Image: Avalanche King County borders the Cascade Range which has a long history of avalanche activity. The Cascade Range receives extensive precipitation due to its size and orientation to the flow of Pacific marine air. In this type of maritime climate, it is common for air temperatures to rise above freezing and for precipitation to change from snow to rain during mid-winter storm cycles. Temperatures can change several degrees within minutes, thus causing abrupt changes in precipitation type. These conditions frequently cause the release of avalanches.

Avalanches occur when a snow pack loses its grip on a slope and slides downhill. Typically, slopes between 20 to 30 degrees and snow packs of 34 inches or more may produce avalanches. Despite the fact that avalanche danger is highest during severe winter weather, most natural avalanches occur in back country little used by humans during such conditions. Uninhabited alpine areas in the Cascades north and south of I-90 experience hundreds of avalanches annually. As a result, this tends to minimize exposure to avalanche impacts. Most at risk are travelers and winter recreation enthusiasts using Steven's Pass in northern King County, Snoqualmie Pass in central King County, and Crystal Mountain Ski Area near Chinook Pass in southern King County. Also at risk from avalanche events are recreation areas that support snowshoeing, alpine and cross-country skiing, snowmobile areas, and winter hikers and campers. Injuries to recreational hikers, skiers, snow boarders, and climbers usually occur outside managed areas.

Between 1910 and 2005, avalanches in Washington State killed over 200 people. This total far exceeds deaths in Washington from any other natural cause during that time frame. Accounting for a large portion of this number is the 96 people who were killed in the Wellington disaster in 1910. More recently, between 1995 and 2005, 24 people in our state died due to avalanches. The majority of those killed from avalanche in the United States since 1997 were involved in the types of activities noted above.

 /Hazard-specific Preparedness Steps

  1. Check out area avalanche conditions before you venture out.
  2. Tell family/friends where you are going, what route you will be taking, and when you expect to return.
  3. Complete a Wilderness Trip Plan (external link) and give it to a family member or friend before you go.
  4. Bring along the appropriate equipment and supplies for winter conditions and the activity you're involved in. Be prepared in the event you get lost or separated, including a method for communication such as a two-wave radio. Pack dry clothing, waterproof matches and paraffin fire starters with you.
  5. Pay attention to and abide by posted signs and regulations.
  6. Stay aware of your surroundings. Learn the indicators and signs for avalanche and know what to do if you're caught in one. 
  7. Be prepared to take emergency shelter. 
  8. Keep an updated disaster supply kit in your vehicle.
  9. Establish meeting places and phone numbers in case family members are separated and your home is impacted.
  10. Be sure to keep at least a half-tank of gas in your vehicle at all times. Someone may need it to get help, or you could be delayed for long periods of time or have to reroute if a pass is temporarily closed for avalanche control.
  11. See "severe storms" section for more information on winter storms and cold weather.

/ General Preparedness Steps

  1. Have and practice a family disaster plan.
  2. Establish meeting places and phone numbers in case family members are separated.
  3. Identify an out-of-state contact to call during a major disaster or emergency; it will be easier to call out of the area if local lines are tied up.
  4. Make sure everyone knows when and how to call 9-1-1.
  5. Keep your disaster supply kits up to date. Make sure you have kits for your home, vehicle, work and school.
  6. Get a tone-alert NOAA Weather Radio to receive emergency notifications and up-to-date information and instructions.
  7. Teach all family members when, where and how to turn off utilities. Make sure you have the appropriate equipment, such as a wrench, handy.
  8. Make sure you understand the emergency plans and expectations at your child's school and your work.
  9. Preplan alternate transportation routes to and from work and other important destinations.
  10. Be sure to keep at least a half-tank of gas in your vehicle at all times; power outages often accompany disasters and gas stations rely on electricity to power their pumps.
  11. Know ahead of time what you should do to help family, friends or neighbors who are elderly or have special needs.

See the following "related links" for more details on how to prepare for, respond to, and recover from this type of a disaster or emergency.

Related Internal Links

Related External Links