January 13, 2017

Avalanche Danger Update & Weekend Avalanche Outlook

Dangerous avalanche conditions are expected to develop throughout Chugach State Park Friday into Saturday due to new snow and wind.  Danger is expected to continue to rise through the Martin Luther King Jr. holiday weekend due to wind and another round of snow Sunday into Monday.

Natural avalanches are possible, and human triggered avalanches likely.

Cautious route-finding, conservative decision-making, and careful snowpack evaluation are essential.  Small avalanches may occur in many areas, large avalanches in specific areas, and very large avalanches in isolated areas.

Many avalanche accidents that have happened in Anchorage’s backyard of Chugach State Park could have prevented by just a basic level of avalanche awareness.  If you don’t have this level of awareness, here are some online resources to help you start the learning process.  There are also a lot of options for getting a real avalanche education throughout the state.  Many of these learning opportunities are even FREE.  Here’s info on a free opportunity to learn about avalanche safety and rescue at Hatcher Pass tomorrow.

A winter weather advisory has been issued by the National Weather Service.  Snowfall is expected to be the most intense between midnight and early Saturday morning with 4-8″ accumulation.  Accumulation could be significantly higher in the mountains.

Recognize red flags of avalanche danger.  Acknowledge increased danger from new snow and wind.  Be on the lookout for recent avalanches.  “Whumphing,” or collapsing, and shooting cracks are glaring red flags.

Wind will further increase avalanche danger in the mountains on leeward and cross-loaded terrain.  This terrain consists of upper elevation slopes near peaks, along ridges, and along gully sidewalls.  Winds vary throughout the park.  Areas with deeper, especially bulbous, snow along leeward ridges and gully sides; wind loaded snow below cornices; and snow that’s denser, especially if exhibiting cracking or a hollow feel, will be the most dangerous.  Cornices will grow and be less stable.  A cornice fall poses an inherent hazard, as well as its potential to trigger an avalanche.  Avalanche danger may continue to increase from wind loading even after snowfall diminishes.

Be mindful of terrain traps, and exposure to overhead avalanche danger.  Avalanches triggered in the upper elevations have the potential to run into lower elevation, even flat, terrain.  Many trails in Chugach State Park cross dangerous avalanche paths (including Penguin Ridge, Falls Creek, Rabbit Creek, Powerline, O’Malley Gully, South Fork Eagle River, and Iditarod-Crow Pass).  A basic level of avalanche awareness, such as that gained through a free or low-cost class, will help you be able to identify problem areas.

Chugach State Park has not had enough snow fo reasonable backcountry travel by ski, but that may change this weekend.  Approach slopes with caution.  The snowpack under the new snow is variable, but where it exists there are potentially dangerous persistent weak layers.  Hazards such as exposed or only superficially covered rocks and vegetation exist.