Avalanche forecast

Mount Shasta

Mount Shasta Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Westerly winds have crafted slabs on NW-N-NE-E-SE aspects near and above treeline. Areas prone to drifting should be avoided or assessed with care. Instabilities will be greatest on steep, convex terrain features that hold signs of active or previous wind drifting. Safe travel behaviors, clear communication, and snowpack assessment are risk management tools for today. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Elevated avalanche conditions will start the day off near and above treeline. Over the last 24 hours, winds have blown from the south, west, and northwest, averaging a speed of 15 mph, with a predominant westerly direction. The nine inches of recent storm snow have been formed into thick and thin drifts on leeward NW-N-NE-E-SE aspects. Today, an additional few inches of snow will allow for continued loading, increasing the size and sensitivity of existing drifts. Freshly loaded slopes directly below or near ridgelines, rocky terrain features, and convex rollovers are likely trigger points. Surfaces that present signs of wind effect and hold cohesive properties indicate the existence of a wind slab.    Slabs and sluffs of storm snow are possible on any steep protected aspect near and below treeline where five or more inches of unconsolidated snow exists. Underlying firm bed surfaces will make it easy for any kind of avalanche to run moderate distances and hold the risk of knocking unsuspecting riders off their feet and carrying them through unforgiving terrain.    Observe for recent avalanche activity, signs of instability, and self-assess suspect snow to gain a better picture of the trend in conditions.

    (3/10/2024)

    Cracking. A red flag of avalanche danger, which signifies present surface instability. 

    Photo: Samuel Clairmont

Avalanche Discussion

Yesterday's observation near treeline in the Old Ski Bowl revealed a moderate amount of blowing snow, small freshly formed drifts, and wind lips reactive to skis on leeward aspects. All the new snow sits atop previously formed surface crusts, which range in thicknesses given aspect and elevation. The crusts have proven to be supportable to the new snow load, skis, and snowmobiles. However, boots still penetrate through.    A moderate amount of uncertainty exists above treeline regarding the amount of new snow and the rate of loading. It's fair to assume large D2 avalanches lurk and are possible to trigger given the right circumstances.  Wind loaded slopes and variable surfaces along ridgelines were the previous surface conditions before this recent storm. It's unsure how the new snow will bond to the old surfaces, and if previous wind loaded areas have enough strength to receive and support a new load.   The storm has resulted in a general warming to cooling trend, which is ideal for bonding capabilities of new snow to old, and helps support a right-side-up snowpack structure. Nevertheless, over the last 24 hours, interfaces within the storm snow may have formed during periods of brief temperature swings and incremental snowfall rates. These instabilities may be present today.    24 hour Storm totals: Mount Shasta ~ 7.8 inches  Mount Eddy ~ 8.5 inches  Castle lake ~ 6.3

Regions covered