Haines Avalanche Center

Forecast Expired - 12/17/2021

Above 2,500ftModerate

1,500 to 2,500ftModerate

Below 1,500ftModerate

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Persistent Slab:

Aspect: All aspects, most likely on wind loaded aspects and features SW-S-SE-E.

Elevation: All elevations, mainly at and above treeline.

 

Bottom Line: While triggering an avalanche has become more difficult, strong over weak layering in the upper snowpack could still produce a slide. Remain vigilant around suspect terrain such as, on exposed slopes greater than 30 degrees, below ridge-lines and in couloirs/gullies. If you venture into new terrain, keep in mind false positive confidence. Very cold temperatures continues to weaken snow at the surface and layers of concern deeper down.

 

Travel advice: Use safe travel techniques such as only exposing one person at a time both on the way up and down. Group up in safe zones that are out of harms way. Have good communication, including radios and a set plan in case of an emergency. Be practiced at companion rescue, identify potential hazards, and avoid possible trigger points on a given slope.

 

Identify old wind slab by looking for stiff or hollow surface snow, and looking for cracking, whumphing – treat these areas as highly suspect. You can find safer conditions in wind-protected areas with softer snow. Avoid terrain traps where snow could pile up quickly, or the consequences of a slide could cause injury or death.

 

The persistent slab danger is not healing, it is standing by waiting for the right trigger. Keep in mind that most avalanches are triggered by someone in the group.

 

  • Snowfall Dec. 6-10th alternated with wind events and was blown around by strong NW winds on Dec. 11th
  • Cold temperatures Dec. 3-5th created weak snow at the surface that is now buried in many places
  • Over a meter deep: old weak layers are buried and difficult to trigger but still reactive.
  • Toward the very bottom: early season snowfalls and crusts linger and are very difficult to trigger but are still of concern.

 

It is still possible that any surface avalanches could step down to deeper weak layers, the October rain crust, or even the ground in alpine areas. 

 

 

Surface layers from Dec. 16th / Test pit results from Dec. 9th  / Full profile from Dec. 8th

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

This natural avalanche occurred on Dec 11th on Old Faithful during the recent wind event. It ran on a cross-loaded NE aspect at 3200ft, running on the October rain crust. It shows that given a heavy new load, this persistent weak layer can activate and cause a large avalanche.

Weather

A weak surface low will provide very light snow accumulations today with low to moderate West winds. Not much is expected to change with our cold and dry weather outlook.

  • A strong NW wind event began on Dec. 11, causing active wind loading
  • Early December has brought in about 2-4 feet of snowfall
  • November brought consistent heavy snowfalls, cold weather, and SE winds
  • October brought heavy snow in the alpine, followed by a few rain/sun crusts
 Snow Depth [in] Last 24-hr Snow/SWE [in] Last 3-days Snow/SWE [in]  Today’s Freezing Level [ft]  Today’s Winds Next 24-hr Snow/SWE
Mount Ripinsky @ treeline **   64″  0″ / 0.0*  0″ / 0.0*  0′  light, W  2″ / 0.10*
Flower Mountain @ treeline  45″  0″ / 0.00  0″ / 0.0*  0′  light, W  1″ / 0.05*
Chilkat Pass @ 3,100ft  19″  0″ / 0.00  0″ / 0.0*  0′  light, W  0″ / 0.00*

( *star means meteorological estimate )

** The Ripinsky weather station is in need of repair, and will likely be down until Summer.

Additional Information


Be prepared for an emergency and hypothermia. Winter is a high consequence environment. Carry bear spray.


Become a sustaining Haines Avalanche Center Member by clicking the poster or visiting alaskasnow.org/joinHAC. Support local forecasts, observations, education and weather stations. Join a community of winter recreationalists. Benefit from collective knowledge and skills. Help keep your friends and family safe in the backcountry. Get a free limited edition mountain buff, or neck gaiter with a $50 membership (first 20 members!).


 

Practice like you play. Make sure all your rescue gear is fully functional and your beacon has NEW batteries. Make sure 1) everyone in the group has a functioning beacon, shovel and probe 2) knows how to use them and 3) has trained in companion rescue in the last year. Keep your skills fresh. If you head into the hills, watch out for red flag avalanche conditions, natural avalanches, whoomphing or collapsing, and shooting cracks.

 

Education Video Links:

Announcements

Bottom Line: While triggering an avalanche has become more difficult, strong over weak layering in the upper snowpack could still produce a slide.  Thursday, Friday, Saturday and Sunday forecasts have begun. Click the –Full Forecast– button below for more details. Please submit your observations!