Hatcher Pass Avalanche Center

Hatcher Pass Avalanche Forecast RSS

Archives
ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sat, November 20th, 2021 - 7:00AM
Expires
Sun, November 21st, 2021 - 7:00AM
Forecaster
Allie Barker
The Bottom Line

LOOSE DRY avalanches will be possible to human trigger today at mid and upper elevations on all aspects, on slopes steeper than 40º.

Sluff management will be critical to avoid being swept over rocks or into terrain traps.

Keep those scarfs and ear muffs handy as cold clear weather will continue to persist throughout the weekend.

 

Special Announcements

HPAC is still accepting applications for the Johnny Soderstrom Memorial Scholarship. Click here for more info. Applications are due by Nov 26th.


Do you ski or ride regularly at HP? HPAC depends on all user groups to sustain our non-profit. Be part of the team. Donate now! Thank you

Thanks to our sponsors.
Sat, November 20th, 2021
Upper Elevation
Above 3,500'
Moderate (2)
Avalanche risk
Mid Elevation
2,500'-3,500'
Moderate (2)
Avalanche risk
Low Elevation
Below 2,500'
Low (1)
Avalanche risk
Upper Elevation
Above 3,500'
Avalanche risk
Moderate (2)
Mid Elevation
2,500'-3,500'
Avalanche risk
Moderate (2)
Low Elevation
Below 2,500'
Avalanche risk
Low (1)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Recent Avalanches

Numerous small human triggered dry loose avalanches (sluffs) occurred this week on  all aspects on slopes 40º and steeper.

Above: Marmot 3800′ SW 11/19

Above: Ridge btw Skyscraper and Martin Mine 4000′ E 11/19

Avalanche Problem 1
  • Dry Loose
    Dry Loose
  • Almost Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic
    Very Large
    Large
    Small
    Size
Dry Loose
Dry Loose avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

Likelihood of Avalanches
Terms such as "unlikely", "likely", and "certain" are used to define the scale, with the chance of triggering or observing avalanches increasing as we move up the scale. For our purposes, "Unlikely" means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. "Certain" means that humans will be able to trigger avalanches on many slopes, and natural avalanches are expected.

Size of Avalanches
Avalanche size is defined by the largest potential avalanche, or expected range of sizes related to the problem in question. Assigned size is a qualitative estimate based on the destructive classification system and requires specialists to estimate the harm avalanches may cause to hypothetical objects located in the avalanche track (AAA 2016, CAA 2014). Under this schema, "Small" avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become "Large" enough to bury, injure, or kill people. "Very Large" avalanches may bury or destroy vehicles or houses, and "Historic" avalanches are massive events capable of altering the landscape.

Signal Word Size (D scale) Simple Descriptor
Small 1 Unlikely to bury a person
Large 2 Can bury a person
Very Large 3 Can destroy a house
Historic 4 & 5 Can destroy part or all of a village
More info at Avalanche.org

Small, loose dry avalanches (sluffs) will be possible to human trigger today at mid and upper elevations on all aspects, on slopes steeper than 40º.  Natural avalanches are unlikely.  Sluffs will be small in size but very capable of catching and carrying you into other unfriendly hazards such as rocks, and terrain traps, compounding the risk.

Above: 11/19 Video from Martin Mine, East aspect, approximately 4000′ in elevation. A quick hand pit shows weak snow throughout the snowpack, lacking any flaws or layers of concern.

 

Sluffs have been moving faster and catching seasoned backcountry enthusiasts off guard the last few days as cold weather continues to facet out the snowpack.

The good news is that sluffs are a manageable avalanche problem, however, managing them takes skill. Ski cutting this avalanche problem can be very effective.

Choosing slopes that lack terrain traps, have appropriate coverage, and lack glide cracks will significantly improve your margin of safety.

Snowpack depth is still variable at Hatcher Pass ranging from 1 to 3 feet deep. Early season hazards still exist with buried rocks and tundra.


Saturday evening

Be on the lookout for winds that are forecasted to increase Saturday evening NE 20-30 mph.  There is some uncertainty with this forecast. Any wind, even for a short duration will easily transport low density snow and build sensitive wind slabs on leeward  aspects (South to West). If winds increase tonight , expect the avalanche danger to rise.

Weather
Sat, November 20th, 2021

NWS Rec Forecast here.

NWS point forecast here.

State Parks Snow Report and Motorized Access information here.

Observations
Recent Observations for Hatcher Pass