Haines Avalanche Center

Forecast Expired - 03/31/2022

Above 2,500ftModerate

1,500 to 2,500ftModerate

Below 1,500ftModerate

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Persistent Slab:

AspectAll, but mainly N-NW-W

Elevation: Near and Above Treeline

 

Bottom Line: Two main interfaces exist in the upper snowpack layers: 1) The 3/20 layer that is about 12″ deep. This first interface is located specifically on N-NW-W aspects and remains possible for human triggers. 2) The deeper 3/4 layer that is now buried under roughly 3ft of snow. It is located on a variety of aspects due to a mix of smooth to rough old snow surfaces from early March’s cold, clear and windy weather. This layer remains stubborn and possible for human triggers. Dense clouds and warming daytime temperatures combined with settlement this week could produce hard slabs that are difficult to predict and require the right trigger point. If the sun comes out today, strong solar radiation could play a big role in slab failure especially near rocks/cliffs.

 

Travel Advice:

  • Identify and avoid shallow areas including trigger points around rocks, cliffs, and trees!!
  • Look for shooting cracks, whumphing or collapsing that indicate a stiffer slab over weaker snow.
  • Avoid terrain trap areas such as cliffs and gullies, and areas where it is hard to escape off to the side.
  • 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.
  • Hard wind slabs can break above you, take into consideration extra safety margins.
  • Persistent slabs are unpredictable, don’t get surprised. Gather information to help confirm suspicions and make assessments.
  • Probe and feel for slabs underneath you.

 

 

Additional Consideration:

  • We believe 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.

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Falling Cornice:

AspectAll

Elevation: Near and Above Treeline

 

Bottom Line: Wind loading last week has built cornices along N-NW-W aspects that may be sensitive to human triggering and possible to occur naturally. 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 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

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.

(Thanks to John Upton for the above photo, which shows a fresh slide below rock features on a solar aspect, from 3/26, Transitional Zone near 4600ft, NW aspect)

 

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

Weather

Forecast:

Thursday will bring a break from the precip, but clouds will likely hang around. There may be a few sunny breaks if we are lucky, especially in the Transitional and Pass zones. Winds will be light. The next series of storms is lined up for Friday-Sunday, with light-moderate accumulations and snow levels remaining near 2000ft.

Seasonal Summary:

  • 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 **  145″*  4″ / 0.60″*  4” / 0.60″*   1000 – 2500′ Light, Var   2″ / 0.20*
Flower Mountain @ treeline  86″  4″ /0.50″  4″ / 0.50″   1000 – 2500′ Light, Var   1″ / 0.10″
Chilkat Pass @ 3,100ft  47″  4” / 0.20”  4” / 0.20”   1000 – 2500′ Light, Var   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.

 

Education Video Links:

Announcements

Spring time is exciting, but remember to keep your stoke in check and in line with the weather and avalanche conditions. Look for whumphing, cracking and natural avalanches. Avoid slopes with strong solar radiation, wind loading, increasing temperatures and cornices. Click the  +Full Forecast  button below to read the details. Please submit your observations if you head out!