Bulletin d’avalanche

Abajos

Utah Avalanche Center
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Danger d’avalanche

  • Alpin
  • Limite forestière
  • Sous la limite forestière
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

A CONSIDERABLE avalanche danger exists on steep, mid and upper elevation, wind drifted slopes that face NW through E and human triggered avalanches are likely in these areas.

The avalanche danger is MODERATE on low elevation northerly aspects and on mid and upper elevation slopes facing W and SE where you can detect recent deposits of wind drifted snow.

Most S-SW facing terrain has generally LOW danger.

It's also still very low tide out there. Beware of rocks, stumps, and deadfall lurking beneath the surface.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2

    A classic setup of strong snow over weak snow is developing on upper elevation, northerly aspects that retained snow from October. This October snow has become loose, weak, and sugary, or as we say, faceted. This faceted snow has formed a persistent weak layer at the base of the snowpack. Recent and wind drifted snow has formed a dense slab on top of this weak snow creating an unstable situation, and human triggered avalacnhes up to 2' deep are likely on steep, northerly facing slopes at mid and upper elevations.

    Photo illustrates a cohesive slab from the Dec 10 storm sitting on top of loose, weak, sugary faceted snow from October.

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2

    Potentially unstable, recent deposits of wind drifted may be found on upper elevation slopes facing W through N through SE. Wind drifts from on the leeward sides of ridge crests and terrain feaures such as sub ridges, gully walls, or rock outcroppings. On northerly aspects, wind drifted snow has added stress to pre-exisiting slabs with weak, sugary snow underneath. In these areas, human triggered avalanches failing on this weak sugary, are likely. Wind drifts are recognizable by their smooth, rounded appearance and cracking is a sign of instability. Avoid steep slopes with recent deposits of wind drifted snow.

Snow and Weather

Get current and past 24-hour readings from these real-time weather links.

NWS Weather Forecast.

Snow totals and temps at Buckboard Flat (8924')

Snow totals and temps at Camp Jackson (8858')

A long wave trough with an "exceptionally strong jet" remains parked over the West, but as the snow continues to pile up in the San Juans, the story for us continues to be mainly about the wind. Today look for cloudy skies, ridge top SW winds in the 20-30 mph range, high temps in the upper teens, and a chance for developing snow showers by afternoon. Sound familiar? A better chance for snow develops overnight as the next shortwave moves through the area but it seems to be another repeat performance of the last two. 3"-5" are possible with snow showers lingering through tomorow. The models are still showing a storm with a decent shot at some accumulating moisture by the end of the year.

Snowpack

The mountains picked up another inch or two of snow bringing totals up to around 10" since Friday night with locally higher amounts at uppe elevations. Coverage prior to this storm was quite thin with most sun and wind exposed slopes still showing lots of grass and occasional patches of bare ground. Northerly facing slopes above about 9500' have held snow since October, and this old snow has formed a weak, sugary, faceted layer at the base of the snowpack and this is where the trouble is. Recent and wind drifted snow has formed a dense slab over top of this weak, sugary snow and human triggered avalanches on steep, wind drifted slopes that face NW through E are likely. On slopes facing W and SE you may find unstable deposits of wind drifted snow. Wind drifts are recognizable by their smooth, rounded appearance and cracking is a sign of instability.

Matthew Cozart was up yesterday and he reported wild, windy weather and unstable avalanche conditions. Read his observation here.

General Announcements

Who's up for some free avalanche training? Get a refresher, become better prepared for an upcoming avalanche class, or just boost your skills. Go to https://learn.kbyg.org/ and scroll down to Step 2 for a series of interactive online avalanche courses produced by the UAC.

This forecast is from the U.S. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.

Régions couvertes