Haines Avalanche Center

Forecast Expired - 03/04/2023

Above 2,500ftConsiderable

1,500 to 2,500ftConsiderable

Below 1,500ftModerate

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Wind Slab:

The Bottom Line: Wednesday brought about 12″ of new snow to this zone, combined with strong SE winds in the alpine. Reactive slabs of wind drifted snow in the alpine will be lurking in wind loaded areas. These slabs rest on weak storm snow and facets. Human triggering is likely on slopes steeper than 30 degrees. Wind slabs can be avoided by sticking to sheltered or wind-scoured areas. Also from the wind, cornices might be unsupported, scoured, and weak. Tread carefully around them and limit your exposure to slopes below them. A cornice drop could cause a slide, with potential for a step down.

 

The severe consequences of our avalanche problems remain, due to deep persistent layers. Be hypersensitive of terrain- it is an active way to manage our exposure to the risk of an unlikely but high-consequence deep slab avalanche.

 

When on or near avalanche terrain, be diligent on terrain selection, group management, and human factor.  Travel one at a time or with enough spacing so that only one person is exposed to an avalanche path at any one time. Be prepared for an avalanche that could step down to deeper instabilities, creating a slide that could break very wide, and take out all the “safe” zones on a slope. Be extra careful not to group up in places that an avalanche can reach. 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Persistent Slab:

When seeking out wind protected zones, remember that wind-protected pockets may be harboring weak, buried surface hoar layers. Protected means preserved. These mid-pack layers appear to be what failed in this weeks avalanches observed.

 

Buried Surface Hoar Layers:

  • Jan 25th melt freeze crust is about 2-3 feet deep (with recent winds and snow, there is a lot of variability on depth of this widespread layer) sitting on top of it are near surface facets, and buried surface hoar from Feb 1-4.
  • January 10th surface hoar is now buried about 4 feet deep.
     

Feb 10 Flower tree-line small wind slab shooting crack on isolated feature.

 

Feb 10 Flower tree-line 2600′ N NE aspect ECTX.  Found Jan 25 melt freeze/facet sandwich ~2’ down from surface.  Also noted a thin layer of rounding facets in the mid pack and a thick layer of depth hoar.

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 3

Falling Cornice:

Cornices have become very large and weak. They are undercut, overhanging, and slowly sagging as they grow. Strong sunshine and increasing winds will put a lot of stress on these dangerous beasts. Stay way back from any snow ledges or cornices on ridgelines or summits. Some may fall naturally, so do not travel below them. More likely will be human triggering of cornices from above. When a cornice fails, it will break way further back on the ridge than expected and take most of the flat terrain out with it. Any cornice falls are likely to trigger very large and deadly deep-slab avalanches. Consequences are very high right now!

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 4

Deep Slab:

 

Old Melt Layers and Crusts:

 

  • Dec 31 surface hoar layer is present in the Transitional and Pass zones, about 5 ft deep. This layer has been active in pits, and caused some natural avalanches in early January.
  • A buried persistent weak layer about 7+ feet deep (The “Big Warmup” Layer, Formed Nov 17th) is still a concern. Numerous natural avalanches observed 1/27 likely on this layer.
  • A wide safety margin is necessary. This setup could produce avalanches that break wider than expected, and are most likely to be triggered from shallow trigger points like rocks or small trees. You could ride the same slope numerous times until that right spot produces a large destructive slide.

 

“Big Warmup” facet layer in the Transitional Zone at 2500ft on Jan 2 with test results ECTP18 that demonstrated propagation potential on this layer.

.

 

Pit at Old Faithful, 2500’, East aspect on Jan 12. A 5″ thick layer of facets down 170cm. Also, observation noted faceted surface conditions.

 

Depth Hoar at the Ground (Above 3,000′):

  • October snow followed by long cold snaps created depth hoar at the ground in most areas.
  • You are most likely to human-trigger this layer from shallow spots around rocks, or trees, or have a surface avalanche step down to the ground on this layer. Any slides that break to the ground are likely to be deadly.

 

Photos shows 6-9mm advanced depth hoar at the ground down 180cm with ECTP 25 down 80cm on facets below a crust in the Haines Pass Zone at 4,000ft on a NE-aspect.

 

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

March 2: Small natural soft slabs were observed in steep trees in the Lutak zone. This kind of small to large natural activity is likely widespread in the Lutak zone.

Feb 19-23: 6 different observations of natural avalanches in the transitional zone and in the Chilkat range. The natural D2 slides were on all aspects, a few on lower angle, all running on a mid-snow pack layer, and a majority with widespread propagation.

A larger, D3-R4 natural avalanche was observed near Four Winds on a S, SW aspect, down 60-120cm, it looked like a loose wet slide that maybe stepped down to a lower layer. Widespread propagation.

Feb 9: Glide cracks ~3000-3400′ in the transitional zone on N, NE aspects. Also notable was observation of reloading of bed surfaces on previous slides.

Jan 28: Lutak Zone

Glory Hole NW-aspect around 3,200′

Lutak NW-aspect around 3,200' Jan 28

 

Multiple wide propagating natural slides released during Jan 25-29th

 

 

Weather

Forecast:

Friday will bring clearing skies and increasing NW winds. Those NW winds will become strong by Saturday into Sunday, with temperatures dropping into the single digits. We will be under strong high pressure for several days with no storms in sight.

 

Recent Weather Summary:

  • March 1st brought a strong and cold storm, with 10-15″ of new snow inland, and 30″+ in the Lutak zone.
  • Late Feb 20-Feb 23 a cold high pressure system with moderate to strong N, NW winds
  • Feb 19-Feb 20- warmer, solar effect on south aspects, valley fog on the 19th at ~1500-2000 ft.
  • Feb 12 freezing levels 1250ft
  • Incremental snow (more in Lutak zone) since Feb 5th, periods of moderate S/SE winds
  • Feb 1-4 Near surface facets on top of crust from Jan 25 warm-up
  • Jan 17-26 brought around 5″ of precip (3-5feet of new snow above 3000ft), strong SE winds, and a noticeable warmup
  • Surface Hoar and Near Surface Facet growth Jan 8-10
  • A strong front brought 24-30″ of snow above 2000ft on Jan 2nd.
  • There was widespread Surface Hoar growth on Dec 31st.
  • Dec 23-26 brought 10-18″ of new snow and a sharp rise in temperatures from -10F to 30F along with variable winds
  • Dec 16-23 brought strong NW winds and arctic cold temperatures
  • Dec 15 brought warmth/light rain up to 2600ft
  • Complete Season Histories:     Transitional Zone     Lutak Zone

 

 Snow Depth Last 24-hr Snow/SWE Last 3-days Snow/SWE  Today’s Freezing Level   Today’s Winds Next 24-hr Snow/SWE
Mount Ripinsky @ 2,500′  ~145″  0″ / 0.00  34″ / 2.00  0′  mod, NW   0″ / 0.00″
Flower Mountain @ 2,500′  67″  0″ / 0.00 15″ / 1.00  0′  mod, NW  0″ / 0.00″
Chilkat Pass @ 3,100ft  52″  0″ / 0.00 6″ / 0.30  0′  mod, NW  0″ / 0.00″

 

Additional Information

WEAR A HELMET! Be careful of rocks and hidden hazards. Be prepared for crevasses when on a glacier. 

Are your riding companions trained and practiced in avalanche rescue? Everyone in your group needs to have a beacon, shovel, and probe, and know how to use them. Our mountains have very limited cell coverage, carry an emergency communication device and enough gear to spend the night.

Avalanche Canada’s Daily Process Flow – Utilize this everyday you go out in the mountains.

Announcements

Click the +Full Forecast link below for each zone to read more.  If you see any recent natural avalanche activity, or signs of instability please submit an observation.