Haines Avalanche Center

Forecast Expired - 02/05/2022

Above 2,500ftConsiderable

1,500 to 2,500ftConsiderable

Below 1,500ftConsiderable

Degrees of Avalanche Danger

Low
Moderate
Considerable
High
Extreme

Avalanche Problems

Problem 1

Wind Slab:

 

Examples of wind slab formation to help identify possible locations of the now buried persistent slab problem

 

Aspect:  All aspects

Elevation:  Treeline and above.

 

Bottom Line:

Variable wind directions and speeds and snow available for transport could form fresh wind slabs on lee aspects and specific terrain features.  This problem might act as tipping point for deeper persistent problems.

 

Travel Advice:

  • Make solid weather observations that inform the avalanche danger.
  • Look for signs of wind touched snow/terrain features.
  • Look for rapid changes, including heavy snowfall, rising temperatures and wind loading
  • Use low consequence test slopes to identify reactive wind slab.
  • Avoid recently wind-loaded slopes and active loading!
  • Keep an eye out for deeper instabilities, including shooting cracks, whumphing or collapsing that indicate a stiffer slab over weaker snow
  • Be mindful of any terrain that is above you that has the potential to naturally avalanche
  • Stay out of terrain traps where new snow could knock you into a hazard or pile up quickly, such as gullies or tree-wells

 

 

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, especially wind-protected basins, aprons below steep terrain (see photos in Avalanche Activity Section below)

Elevation: Treeline and above.

 

Bottom Line:  SE winds yesterday morning, and then NW winds yesterday afternoon have formed wind slabs below ridges and terrain features.  This problem will be difficult to identify with recent accumulations and new snowfall and wind transport is adding more stress.  Careful snowpack evaluation, cautious route finding and conservative decision making are essential.  Human-triggered avalanches remain possible 1-6′ deep.

 

Travel Advice:

  • Avoid steep wind-loaded slopes!
  • Stick to slopes less steep than 30-degrees while in the alpine. If you choose to venture onto steeper slopes, carefully evaluate them by digging, probing, and testing them. Reduce risk exposure and travel one-at-a-time.
  • Look shooting cracks, whumphing or collapsing that indicate a stiffer slab over weaker snow. 
  • Hard wind slabs can break above you, take into consideration extra safety margins
  • Probe and feel for slabs underneath you

 

 

 

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

First Photo: Deep slab natural avalanche that occurred roughly 1/29 in the Lutak Zone. This slide may have run on a buried facet layer from late December’s outflow event, or even a deeper rain crust near the ground (it went all the way to ground in spots).

Last two photos: From 1/29 to 2/1, several reports came in of recent avalanches in the alpine of the Transitional Zone. The common characteristics of these slides were wide propagation, and failing 2-5ft deep at the interface below the wind slabs from last week’s atmospheric river. We have strong reason to suspect these slides occurred on a buried surface hoar layer from 1/20. They happened on all aspects, at elevations from 3000 – 5000ft, and all were in wind sheltered areas below ridges, features, and starting zones. Slide were observed in the Transitional and Lutak zones, but the Lutak slides appear to be on different layers.

 

Weather

Forecast:

More change.  A nice gift of clearing weather this afternoon before the next warm air/precip upper cut.  South winds will pick up this evening.  Tomorrow will be a gradual build up for next wave on Sunday.

Seasonal Summary:

  • Feb 1st-4th brought in about 10″ of low density cold smoke powder
  • Jan 27-29 brought 1.5 – 2.4″ of SWE with freezing levels near 1500ft.
  • An Atmospheric river hit Jan 21-22. It brought in 2-7″ of SWE (2-5ft of snow above 2500ft, mostly rain below)
  • Jan 9th-15th brought 24-48″ of new snow in the alpine, with some light rain up to 3,500ft, followed by heavier rain up to 2000ft.
  • Very strong NW winds and arctic temperatures blasted the area the first week of January
  • Jan 1st: New snow (20″ in Lutak, 7″ Transitional zone) buried any preserved surface hoar.
  • 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 **  105″ *  0″ / 0.05″*  6″ / 0.20″*  0′ – 1000′  mod, N-S    2″ / 0.50*
Flower Mountain @ treeline  73″  5″ / 0.05″  10″ / 0.50″  0′  mod, N   2″ / 0.50 “
Chilkat Pass @ 3,100ft  28″  3″ / 0.03″  8″ / 0.20″  0′  mod, N   1″ / 0.50*

( *star means meteorological estimate )

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

Additional Information

Safe backcountry travel requires training and experience. You control your own risk by choosing where, when and how you travel. Ride rescue ready. Be prepared for an emergency. Prevent hypothermia. Carry bear spray. Winter is a high consequence environment.

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.

 

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