Lawinenlagebericht

Mount Shasta

Mount Shasta Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 2 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Triggering an avalanche is possible today in two different places: on the recent wind loaded slopes of the upper mountain, and on destabilizing solar aspects due to warming. Both wind slab and wet loose avalanches present a real hazard to backcountry travelers, thus caution must be taken. Monitor solar aspects for excessive warming. Once the surface snow becomes sticky and saturated, it's time to get off of avalanche terrain. If you're going above treeline, watch out for visibly wind loaded slopes, cracking under skis, and actively blowing snow.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    For the most part, yesterday's wind was surprisingly light in low elevation terrain. On Mount Shasta above treeline, however, the northerly wind cranked strong and consistent, visibly blowing snow onto leeward aspects. Northerly aspects have likely been scoured or heavily wind effected by this recent change. All that wind transported snow has likely been deposited onto S-SE-E aspects, with cross loading on SW and NE aspects. Approach these upper mountain slopes with caution, slabs could be big enough to bury you. In north facing terrain, there may still be some lingering wind slabs from the previous storm cycle. Assess upper mountain slopes with caution, looking for visibly wind loaded slopes (a lens shaped surface), cracking under skis, and recent avalanche activity.

    (3/30/2024)

    Skier triggered wind slab. 30 feet wide and up to 8 inches deep. Westerly aspect, near treeline

    Photo: Samuel Clairmont

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Yesterday's warm conditions allowed for the early development of a moistening snowpack. In some, low elevation, wind sheltered areas, wet loose avalanches became reactive. Today, as temperatures rise even higher, expect this problem to become more prevalent. Peak instability will be in the late afternoon, when surfaces have warmed all day and the sun is still high. At this point, surface snow will destabilize at higher elevations, compared to yesterday. As the day warms up, be on the lookout for early signs of warming instability such as boot penetration to the boot top or more, small point release avalanches, and failing test slopes. Once the snow starts to feel deep and sticky, it's time to get off. 

    (3/31/2024)

    Skier Triggered Wet Loose

    Photo: Samuel Clairmont

Avalanche Discussion

High pressure has set in over the forecast area, and the snowpack is changing quick. Yesterday showed early stages of how warming will impact the snow. Below treeline, almost every aspect became moist-wet at the surface. In the most shaded areas, drier snow still exists, but surfaces warmed significantly. This morning, expect a widespread surface crust across all terrain. The crust will likely break down quickly as warming progresses, and there will be a sweet spot where the snow is soft enough to ski, but not too soft to where instability is rising. Once the snow begins to feel unsupportable, deep, and sticky, it's best to get off steep slopes.

Tonight, a poor refreeze is expected. Tomorrow will be the warmest day of the week, a few degrees warmer than today.

Yesterday, forecasters traveled to the Grey Rocks area, to conduct the monthly snow survey. The results of snow survey inform the state of California of total snow accumulations in the mountains. In other words, how much water is available for use throughout the summer. Grey Rock is an important site because it is one of the high points that feed the Sacramento River. As suspected, the snowpack is quite deep up there. The deepest measured core was 150 inches (12.5 feet). Forecasters also found signs of warming instability in the form of a skier triggered wet loose avalanche. Check out the full observation HERE. 

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