Lawinenlagebericht

Bridgeport Avalanche Center

Bridgeport Avalanche Center
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Lawinengefahr

Mon
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

It remains possible to trigger a large slab avalanche that breaks deep in the snowpack on older, weaker snow. Cloudy and warm weather today brings chances of wet, loose snow on southerly aspects. Consider your terrain options and time of day on the slope to avoid these problems. 

Lawinenprobleme

  • Deep Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–3

    A persistent slab problem is one of the hardest problems for backcountry users to manage. We don't get information about the problem by looking at the surface of the snow, and unlike a wind slab or storm slab, this problem can stick around for days into weeks after a storm.  The spatial variability of our snowpack also doesn't offer a consistent picture of the problem across the range.  Where found, this problem sits 3-6 feet within the pack; faceted weak snow sits underneath stronger dense snow. The good news: this weak snow has been healing over time. The bad news: it is still there. Uncertainty around this problem is high, so what can we do?  Good terrain management is your best option, with avoidance at the top of the list. 

    Snowpit tests across the zone have produced variable results. We are in a trend where this layer is getting harder to trigger in our snowpits. Ultimately, the snow still needs time to heal. This layer sits under a dense slab of snow after the major loading event of the February 14-15th storm.  Extended column tests produced propagating results this week, and in other areas, no results. Yesterday, we dug adjacent to a Persistent Slab avalanche that was remotely triggered by a rider and their machine last weekend. We did not get propagating results in our test. Snow grains showed 2-3 mm facets that were rounding, a good sign that this layer could be going dormant soon. 

    (2/22/2025)

    A rider and their machine remotely triggered this slide in Voodoo Bowl, on the weekend of 2/15-16

    Photo: Julian Hanna

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    A warm-up in the snowpack is expected today, with temperatures in the 40's between 8-10 thousand feet. Strong solar radiation on southerly-facing slopes could trigger wet, loose avalanches today. Areas around the rocks will heat up faster earlier in the day and can create punchy rotten snow. Watch out for pinwheels and rollerballs forming in the snow and rolling down the snow surface. Wet, loose snow is hard to escape from and entrains snow as it moves down the slope. Timing your ascent and descent to avoid the heat of the day will reduce your risk of triggering wet and loose snow. 

     

Avalanche Discussion

The snowpack is starting to transition out of cold and dry to wet and warm. Firm and smooth wind effected snow was seen and felt around Sonora Pass this weekend. Solar aspects were heating up in the afternoon sun and snow became wet and punchy. Northerly aspects held chalky firm wind board snow. 

Snow pit tests are showing that the persistent slab problem is healing. While the problem is stubborn and not yet dormant, remember to give yourself a wide terrain margin as uncertainty is still high. Complex terain in and around treeline on Northerly aspects is still suspect to sliding. 

The Valentine Storm, our biggest of the year, brought a widespread natural avalanche cycle along with several feet of new snow. We have been tracking the snow all week, and the deep, persistent instability has shown signs of healing. Some details from this week are summarized below:

An avalanche was triggered in the Vodoo Bowl area by a rider and their machine last weekend. 1 person was caught, carried, and self-extracted without serious injury. Details are sparse, photos of the slide are in the media gallery below. 

A fatality occurred earlier this week in the Tahoe region, a rider was caught in a persistent slab avalanche, more details can be found here. 

The Bridgeport Avalance Center joins the Sierra Avalance Center in offering our sincerest condolences to the family and community affected by this loss. 

A patroller from Mammoth Mountain sustained serious injuries last Friday, February 14, while conducting avalanche mitigation work in bounds at Mammoth ski area and has recently passed away. The Bridgeport Avalanche Center extends our sincerest condolences to the deceased family, friends, ski patrol, and Mammoth Lakes community. More details can be found on Mammoth's Instagram page.  

 

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