Haines Avalanche Center

Forecast Expired - 01/02/2022

Above 2,500ftHigh

1,500 to 2,500ftHigh

Below 1,500ftConsiderable

The Avy Rose shows the forecasted danger by elevation and aspect.

It adds more detail about where you are likely to find the dangers mentioned in the forecast. The inner circle shows upper elevations (mountain top), the second circle is middle elevations, and the outer circle represents lower elevations.

Think of the Rose as a birds-eye view of a mountain, looking down from above. The rose allows our forecasters to visually show you which parts of the mountain they are most concerned about.

WNWNNEESESSW

Degrees of Avalanche Danger

Low
Moderate
Considerable
High
Extreme

Avalanche Problems

Problem 1

Wind Slab:

Aspect: Most likely on SW-S-SE-E-NE

Elevation: Most likely At and Above Treeline

The Bottom Line: 20″+ of new snow fell in the last 48 hours. This new snowfall combined with accelerating winds will exacerbate the stress on an already suspect snowpack, especially on leeward aspects. The rate at which the extreme winds will transport snow will change conditions quickly. Be vigilant of cross loaded gullies, open, steep clearings, and rapidly forming cornices. Natural avalanches are likely in and near the alpine today, and some could be quite large. Avoid all avalanche terrain today. 

Buried surface hoar exists 12-20″ down in isolated, protected areas and will be easy to trigger with human weight, with potential to step down to deeper weak layers, including the October rain crust, and the ground.

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Persistent Slab:

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

Elevation: All elevations.

 

 

Travel advice: Consider any possible slopes harboring surface hoar as guilty until proven innocent. Always use safe travel techniques such as only exposing one person at a time both on the way up and down. Identify and avoid thin areas where weak layers are more likely to trigger a slide from. 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.

 

  • On wind-protected slopes, there is preserved buried surface hoar about 5-10″ deep
  • Snowfall Dec. 6-10th alternated with wind events and was blown around by strong NW winds on Dec. 11th. A repeat of the same conditions occurred with NW winds Dec 19th, followed by 6″ of new snow, and now more NW winds.
  • 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 there.
  • Toward the very bottom: early season snowfalls and crusts linger and are very difficult to trigger but are still of concern for step-down potential.

 

 

The persistent slab danger is not going away, it is standing by waiting for the right trigger. We have not had a crush and flush cycle, or stabilizing event. Keep in mind that most avalanches are triggered by someone in the group.

 

5-10mm surface hoar observed Dec. 18/ Test pit from Dec. 23rd with buried crust 70cm down

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

We had one report of a small skier-triggered soft slab last weekend in the Lutak zone. It was on a cross-loaded S aspect gully, and likely ran on the 12/18 Surface Hoar layer, about 8″ deep.

 

Dec 11th: Natural slide on mount Ripinsky’s back bowl caused by wind loading. It ran over a persistent weak layer on a NE aspect at 3,000ft, was 200ft wide and ran 800ft, with a average slope angle measured on Google Earth of 35 degrees.

Weather

As the latest precipitation cycle moves out, NW winds begin to increase early this morning and will persist for several days.  Extreme NW winds and possibly record cold temperatures are expected into mid-week. Wind chills will be brutal.

  • New snow in the Lutak zone buried any preserved surface hoar. This surface hoar is now 12-20″ deep in isolated protected areas.
  • Moderate NW winds hit exposed slopes Dec 19-20th
  • Surface hoar formed on all aspects and elevations Dec 17-18th
  • December brought in about 2-5 feet of snowfall (highest in Lutak zone), and a few strong NW wind events
  • 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 **   80″*  4″ / 0.20* 20″ / 1.20*  9′ Extreme, NW  0″ / 0.00*
Flower Mountain @ treeline  48″  1″ / 0.05 6″ / 0.30  0′ Extreme, NW  0″ / 0.00*
Chilkat Pass @ 3,100ft  20″  4″ / 0.08 8″ / 0.16  0′ Strong, NW  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 dev.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: Avoid all avalanche terrain in this zone today, especially wind loaded areas. Winds will transport snow at an accelerated rate today and for the next several days. Be cognizant of buried surface hoar that now exists in the snowpack.  Click the –Full Forecast– button below for more details. Please submit your observations!