Haines Avalanche Center

Forecast Expired - 12/10/2021

Above 2,500ftConsiderable

1,500 to 2,500ftConsiderable

Below 1,500ftModerate

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Wind Slab:

Aspect: Wind loaded aspects and features N-NW-W – Specific.

Elevation: All Elevations.

 

We received 8″ of  snow in this zone over the last few days. This snow came in cold, dry, and loose, with little wind. Recent snow accumulations of another 5″ and gusty winds from the east/southeast will increase the avalanche hazard. There is surface snow available for wind transport! Natural avalanches are possible and human triggered avalanches are likely. Wind slabs are expected to be reactive.

 

Look for signs of wind loading that include: cracking, collapsing, shooting cracks, hallow sounds, and strong over weak layering. Avoid wind loaded aspects and features.

 

Beware of  terrain traps (e.g. gully, rocks, dense timber, cliff, crevasse) or areas where snow could pile up quickly. Avoid traveling above or below terrain traps.

 

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 and below terrain features – Specific.

Elevation: Up to 3200′ AKA “the bathtub ring”.

 

Observations from Old Faithful last Sunday found a thin crust with weak snow down 60-70cm near 3,200′ and below. This bathtub ring effect, from lower-elevations to mid-elevation, where freezing levels are more likely to cause crusts and weak layers – should be carefully evaluated. Also, of note was surface hoar formation 12/8-12/9 that could be buried by the incoming snowfall and overloaded by wind slab.

 

Weak facets at the bottom of the alpine snowpack in both zones, and the potential of lingering October Rain Crust with weak layers above and below have not seen a significant avalanche cycle. However, it is possible that any surface avalanches could step down to the deeper layers, or even the ground in certain shallow areas in the alpine. 

 

  • One of the best ways to reduce your exposure to deep persistent weak layers would be to stick to areas of deeper snowpack (>1m deep). But be wary of hidden rocks that can act as trigger points, and thin areas around the margins of a slab.
  • Look and listen for deep whumping! Report any natural avalanche activity on these deeper layers!

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Weather

  • A low pressure system will move into the area with increased precipitation 6-8″, moderate southeast winds gusting strong.
  • We’ve had about 20″ of low-density new snow this week in the Lutak zone, and around 8″ in the Transitional zone.
  • Last week, it snowed 6-14″. Winds switched from SE to NW and increased into typical northerly outflow as temperature plummeted into the single digits.
  • October brought heavy snow in the alpine, followed by a few rain/sun crusts, followed by regular heavy snowfalls in November.
 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 **   67″  5″ / 0.35*  18″ / 1.15*  0′  Mod, SE  4″ / 0.30*
Flower Mountain @ treeline  50″ *  3″ / 0.15  8″ / 0.30  0′  Mod, E  2″ / 0.15*
Chilkat Pass @ 3,100ft  29″  2″ / 0.07  3″ / 0.15  0′  Mod, E  2″ / 0.20*

( *star means meteorological estimate )

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

Additional Information


Beware of deep treewells which can trap a person. It’s deep out there. Be prepared for an emergency and hypothermia. Winter is a high consequence environment. Carry bear spray.


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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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