Haines Avalanche Center

Forecast Expired - 04/16/2022

Above 2,500ftModerate

1,500 to 2,500ftModerate

Below 1,500ftModerate

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Wind Slab:

Aspect: Mainly S and SE, also cross-loaded pockets on other aspects

Elevation: Treeline and up

 

Bottom Line: We had a major NW wind event over the last week. The winds have calmed down, but recent wind slabs will linger on certain S and SE aspects. These new slabs will be stiff, and human triggering is possible. Due to the strong nature of the winds this week, you may find these new wind slabs midway down a slope, in unusual places. Cross-loaded terrain like gullies and couloirs will likely harbor these wind slabs. If you do trigger a wind slab, it will likely be a hard slab that breaks above you.  Be careful to avoid terrain traps where a small slide can pile up deep.

 

Travel Advice:

  • Be vigilant as you travel through the terrain. You may encounter variable conditions and stiff wind slabs mid way down a slope
  • Be especially wary on or near terrain breaks where steepness or convexity increases, behind stands or rows of trees that act as snow fences, and in gullies or depressions where wind deposited snow often accumulates
  • Avoid slopes with stiff, hollow, or slabby snow

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Persistent Slab:

Aspect: W-NW-N-NE

Elevation: Near and Above treeline

 

Bottom Line:  On sheltered W-NW-N-NE aspects we still have a lurking buried surface hoar layer 45-55cm deep. This layer contributed to a natural avalanche cycle on Monday 4/4, with several reports of human triggered slides on slopes greater than 35 degrees. Human triggered slides are are still quite possible on this dangerous and tricky layer. Expect this danger to be slow to improve… it will take a good crush-and-flush or a big wet slide cycle to put this one to bed. Deeper weak layers from early March, 1 meter deep or more, still have potential to step down especially around shallow trigger points, or from heavy triggers.

 

Travel Advice:

  • Avoid avalanche terrain on any aspects protected from the SE winds. W, NW, N, and NE aspects especially should be avoided.
  • Use cautious route finding. Be aware of the terrain above you, especially with low visibility. Remote triggering is possible.
  • Identify potential trigger points, or overhead hazard where slides could initiate from, or cause deeper layers to fail.
  • Dig snow pits, run stability assessment tests, probe for strong over weak layers, use evidence to backup decision making. 
  • Look for safer riding that can be found in the trees, and on low angle slopes (less than 30-degrees) without overhead hazard.
  • Avoid terrain traps where snow can pile up quickly, or expose you to hazards such as rocks, trees, or cliffs.
  • Keep wide safety margins near any avalanche terrain – and Be Patient.

 

Additional Consideration:

  • We believe mid-winter deep persistent layers are currently dormant. However, you could still trigger a deeper persistent slab in thin or shallow snow, even if we haven’t had recent feedback or avalanche activity.
  • With the beginning of March comes a higher sun angle than we have seen for the last couple months. Surface warming will begin to be prevalent on solar days, especially around exposed rocks and creating thin and/or weak spots where you could trigger these deeper layers.
  • A variety of wind loading patterns throughout the season have created sizeable cornices on all aspects near mountain tops and ridgelines. Beware that cornices can break much further back than expect, can trigger deeper persistent weak layers and are sensitive to warming, temperature changes and direct sunlight.
  • Remember that persistent slabs are unpredictable and that tests and observations can be unreliable. A probe can be very helpful to determine snow depth and presence of deeper buried weak layers by noting resistance as the probe moves through the snow.
  • Continue to utilize safe travel protocol, wide margins of safety, and collect more information when it comes to entering committing terrain.
  • Loose snow avalanches over terrain features will be amplified by direct sunlight and increasing temperatures during the day, avoid overhead hazard by utilizing timing.
  • Glide cracks have began to appear across the range.  They are very difficult to predict, so basically just avoid exposure near or under.

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 3

Falling Cornice:

AspectAll aspects, on ridgelines and summits

Elevation: Near and Above Treeline

 

With a long winter of various loading directions, cornices have built on all aspects. This unique avalanche problem is less predictable than most and does not have solid tests and observations to better understand likelihood of release. Major factors that do contribute to cornice fall are strong solar radiation, increasing temperatures and recent wind events. Those three have been present recently and as the angle of the sun increases, fragile and sensitive cornices that have hung on all winter may finally begin to break down and fail. Cornice failure can also result in a heavy trigger for slopes below, especially with a persistent slab problem. Any strong solar radiation, or warming could play a big role in cornice failure.

 

Travel Advice:

  • Avoid traveling along or underneath corniced ridgelines.
  • Due to multiple wind directions, cornices may be present on both sides of a ridgeline.
  • Look for signs of drooping cornices from the sun, increasing temperature, or recent wind loading.
  • Understand cornices often break further back onto ridge tops than expected.
  • Observers may underestimate sun’s effect on the back of cornices when traveling on cool, shaded aspects.
  • Cornice fall chunks may not look large but have significant mass and can be destructive or trigger slope below.

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

April 13-15: Size 1-2 natural wind slab avalanches were observed in steep cross-loaded terrain from the Transitional Zone to the Pass.

 

April 3-5: Numerous natural and human-triggered slides were reported from multiple aspects. Crowns were 30-150cm deep, running in fresh storm snow, loose, wind slabs, and a few deeper persistent slabs and cornice drops. The main concern appears to be a surface hoar layer that formed 3/27. This layer is about 35-45cm deep on average.

A human triggered D2-R3 slide at 5200′ on a N-NE aspect 3/4 at the Haines Pass. Crown depth was 35cm. Photo credit: Carver Colbek

3/21-26/2022 – A variety of natural slides were observed 3/26 with the majority of them D1-D2 slabs, 15-30cm deep,  mostly within the new wind-loaded snow on N-NW-W aspects. These avalanches mostly occurred below rocks, ridgelines, or cornices. Some stepped down to deeper layers from early March.

A fresh slide below rock features on a solar aspect, from 3/26, Transitional Zone near 4600ft, NW aspect. Photo credit: John Upton

3/5-7/2022 – Numerous D1-D2 natural and human triggered activity 2-12″+ deep were reported on multiple aspects above treeline.

1/29/2022 – Deep slab natural avalanche that occurred roughly 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).

1/29 to 2/1/2022 – 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.

4Winds zone.  SW.  4000-5000′

Near Mt. Krause

Weather

Forecast:

Quiet weather all across the region will continue to be the trend, though some clouds are expected to roll in Saturday and Sunday. Winds should remain light and diurnally driven, with cold nights, alpine high temperatures below freezing, and occasional strong sunshine if the clouds break up.

 

Seasonal Summary:

  • April 10-13: a strong arctic outflow event brought NW winds up to 50mph and much colder temperatures.
  • April 1-5: Several storms brought in a total of 1.4″ of SWE, with snow levels hovering near 1500ft. Southeast winds were strong.
  • March 29th light accumulations with higher totals 5-10″ observed further up valley.
  • March 28th SE-E winds were moderate gusting strong noted from Haines Pass Wx Station.
  • March 26-27th surface hoar formation was observed due to calm clear cold conditions.
  • March 21-22nd precipitation totaled 0.5 – 1.5″ of SWE with higher totals in transitional zone. SE-E winds were moderate gusting to strong and freezing levels ~1500′.
  • March 11th-17th precipitation totaled 1-1.5″ of SWE snow levels up to 2,000′ with south to north winds.
  • March 3rd-7th reverse loading event with south winds, then north winds, continued diurnal temps.
  • Feb 28th-March 4th saw diurnal temperature swings followed by light accumulations of 2-4″.
  • Feb 16-19th light snow 3-4″ with freezing levels reaching 1,500′ with strong south winds.
  • Feb 12-14th had freeze/thaw cycles that locked up the snowpack to ~4,000′.
  • Feb 5th-9th brought snow levels near 3,500ft, and 2.5-4″ of SWE with strong south winds.
  • Feb 1st-4th brought in 12-24″ of low density 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 **  140″*  0″ / 0.00″* 0” / 0.00″*   700′ Light, SE   0″ / 0.00*
Flower Mountain @ treeline  87″  0″ / 0.00″ 0″ / 0.00″  500′ Light, SE   0″ / 0.00″
Chilkat Pass @ 3,100ft  48″  0″ / 0.00” 0” / 0.00”   0′ Light, SE   0″ / 0.00”

( *star means meteorological estimate )

** The Ripinsky weather station is in need of repair, and will likely be down until Summer. Make a donation to the Haines Avalanche Center for next season here.

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.


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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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