Avalanche forecast

Lutak

Haines Avalanche Center
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Avalanche danger

Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The avalanche danger is HIGH at all elevations. Warm temperatures continue with freezing levels around 3,500ft and light precipitation. As wet snow at the surface on slopes greater than 30 degrees begins to fail,  buried weak layers 2-4ft deep could also begin to release naturally. This is a day to avoid high-consequence avalanche terrain including run-out zones and terrain traps while temperatures remain above freezing. 

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2

    Warming temperatures with rain on snow will weaken the snow surface, causing it to lose cohesion and slide down slopes. As temperatures rise and new snow that has fallen over the past few days warms up, expect wet loose avalanches on all aspects and elevations. Point releases can start small and entrain additional snow that is difficult to escape from and could push you into cliffs or trees.

    Where the snowpack has been heavily saturated by rain on snow over the past days, free water could further weaken buried layers. This could cause persistent and deep slabs (see Problems 2 and 3) to release naturally or get triggered from a surface slide or cornice fall. How far you sink into the snow can tell you how warm the surface is and how close to affecting a weak layer you could be.

    Point releases provide information about the surface snowpack layers becoming weak and sliding. Larger point releases mean less cohesion.

    Photo: Sawtooth Avalanche Center

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3

    Weaknesses within the snowpack are still present and demonstrating propagation potential. A significant slab has formed over an old snow surface from the extended cold period of northerly outflow winds. 3-4"+ of snow water equivalent (SWE) has now been loaded over that weak snow interface. Closer to the surface is a wind slab that formed Thursday from moderate S-SE winds that switched SW-W.

    Persistent slab avalanches often fail without warning signs, propagate wider than anticipated, and can be remotely triggered. They are a low feedback problem, meaning you could ride the same slope numerous times until someone hits a shallow trigger point and initiates a slide. We can reduce the risks by staying off slopes greater than 30 degrees. Warming temperatures make the problem worse (see Problem 3).

    (3/10/2024)

    A consolidated slab of new snow sits over the soft and weak old snow surface that failed with propagation. 2,500' N-Aspect ECTP26 down 70cm.

    Photo: Jeff Moskowitz

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–4

    The combination of warm temperatures, wind loading, and significant precipitation may cause deeper layers that have been dormant to wake up. These widespread melt-freeze layers formed during warm weather events have now been buried 4-8 feet deep. A big trigger like a surface avalanche or cornice fall could step down into these deeper layers, causing a failure to propagate across multiple features.   While a return to colder temperatures and solid refreezing overnight could put these layers back to bed, we should not underestimate them. Avoid avalanche run-out zones and consider the distance a slide could run when thinking about safe zones. Give these slopes time to adjust to changes in the weather, such as soon after heavy snowfall/rain, wind loading, warming temperatures, and strong sun.

    (3/6/2024)

    Notable deep persistent weak layers include the End of Year (EOY) crust visible below the pencil that still has faceted snow around the crust. See the forecast discussion and seasonal weather history tab for more information.

    Photo: Haines Avalanche Center

Avalanche Discussion

Greener pastures may be around the corner after this unsettled weather, until then we are teetering on the edge of a widespread natural avalanche cycle. This means we need to manage the terrain if we choose to go out, which would be considering any potential avalanche path and where critical terrain decision points would be. While some avalanche paths are easier to identify, others are more difficult. Wide safety margins can help us eliminate potentially hazardous areas by avoiding them. Pay attention to warming temperatures, recent wind loading, and rain on snow. Mid-elevations are likely to prove the most difficult to assess due to recently elevated temperatures and the presence of crusts and weak layers.

Notable layers in the snowpack:

  • Freezing levels spiked to 6,000ft
  • 3-4" of SWE from 3/6-3/16 & wind loading from 3/14
  • Northerly outflow wind event- 50-100cm+ deep-Protected = preserved, near-surface facets or "recycled powder" formed in terrain protected from wind.-Extreme winds formed wind slabs that are now buried persistent layers.
  • Valentine's warm inversion, down 80-120cm+: mix of melt-freeze crust, buried surface hoar, and hard sun-warmed surfaces.
  • The late January Pineapple Express crust. An intense precip event saw pooling and percolation with warming to 5,000ft.
  • End-of-Year Crust (EOY). Wet and warm end of last year, freezing levels to 4,000ft.

  Early-mid March has historically come with avalanche accidents in our valley. As part of your trip plan, establish a mindset for your group before you venture into the mountains. This can help combat human factor bias and heuristic traps. Use weather, avalanche, and terrain checklists. Deploy ALPTruth:  

The ALPTRUTH acronym covers 7 contributory factors to avalanche accidents.  When reviewing over 1000 avalanche accidents, Ian McCammon found that 3 or more of these factors were present in over 90% of accidents.

  • A: Avalanche. Have there been any recent avalanches (within the last 48 hours)?
  • L: Loading. Has snow, wind, or rain loaded the slope in the last 48 hours?
  • P: Path. Will your planned travel path cross an obvious avalanche path? Will your uphill travel cross any potential avalanche paths?
  • T: Terrain trap. Is there a terrain trap? These include gullies, trees, cliffs, or other features. A slide into a terrain trap will increase the severity.
  • R: Rating. What does today’s avalanche report look like for your area? If there’s a rating of “considerable” or higher, you may want to reconsider.
  • U: Unstable snow. Have you heard any cracking, collapsing, whoomping? These are clear signs of instability.
  • TH: Thaw. Has there been recent warming of the snow’s surface due to sun, rain, or air temperature? Warming can increase instability and avalanche risk.

Thinking ahead:

  • When the next loading event happens, is it slow and incremental or rapid and significant?
  • What are the temperatures, steady and moderate, spring diurnal, or are freezing levels rising?
  • How does the likelihood of propagation increase or decrease with strength vs. structure?
  • Is there weak snow above or below a crust? How strong or brittle is the crust? Does the crust laminate well to layers above/below or not?
  • Could strong solar radiation or warming temperatures contribute to instabilities, including cornice fall?

Click here for a detailed season weather & snowpack history.

The people you go out with, how you communicate, and how you practice risk reduction as a team throughout the day are equally important as the conditions. Always practice safe travel techniques and terrain management- only exposing one person to a slope at a time, avoid grouping up in run-out zones, and re-consider islands of safety to truly limit your group's exposure. Carry radios, first-aid, and a two-way emergency communication device. Take an avalanche course, and practice companion rescue often with your riding group. Every scenario is different, so it pays to be prepared.

Help us gather information about weather, snowpack, and avalanche activity by reading and submitting field observations. Useful observations can be anonymous and include: 

  • Avalanche Activity: Natural or human-triggered
  • Signs of Instability: Cracking, collapsing, or whumping
  • Red Flag Weather: Precipitation, wind loading, warming temperatures and rain-on-snow
  • Persistent Weak Layers: Surface hoar growth, snow depth, persistent weak layers, etc
  • Snow Pits: Stability test results, layers of concern, total snow depth, location, elevation, aspect, etc 

Were you caught, carried, injured, or buried in a slide? We can benefit from anonymous lessons learned. Please report incidents to Haines Avalanche Center staff confidentially.

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