Bollettino valanghe

West Slopes South

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Strong winds could transport snow to create Wind Slabs by the end of the day on Tuesday. Look for larger slabs in areas prone to east winds or where more snow is available for transport. Steer around steep terrain features if you see shooting cracks or find the wind has stiffened the snow.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Wind Slabs may develop by the end of the day on Tuesday as windspeed increases in the West South zone. If any new snow falls from the sky on Monday night it will be minimal, but low-density snow from the past few days will be available for the wind to transport. Areas near the volcanoes may have more snow available for transport, but throughout the zone, slabs should increase in size as you ascend in elevation and as the day wears on. East winds are expected with this event, which can often create unusual loading patterns, particularly near the crest. So keep an eye out for textured snow surfaces, freshly building cornices, or active wind transport to let you know where the snow is being distributed. Those unusual loading patterns sometimes result in cross-loaded gullies, midslope pockets, or different leeward slopes than you are used to. Avoid terrain features where you notice pillow-like piles of snow or the snow is no longer light and fluffy.

    (1/24/2021) This skin track test at White Pass showed the ability of some wind-affected snow to propagate a fracture this past weekend. [NE aspect, 6200'. Photo: Nate Hough-Snee]

Avalanche Discussion

Snow depths above the 1/13 crust may vary around the zone, but the general snowpack structure and potential issues remain in alignment. In terms of avalanche hazard, we continue to consider the 1/13 our “new ground” and are only concerned about instability above this layer. Sitting above this firm crust, we have new snow, multiple types of buried weak snow, and smaller crusts. In areas such as Paradise, there is more new snow above the crust, while in areas such as Crystal, there is potentially more weak snow. Regardless, we have not had many avalanche concerns recently despite weak snow sitting atop a firm crust, because there hasn’t been enough depth or existence of a slab. With the addition of strong winds to the zone by the end of the day on Tuesday, Wind Slabs could form, providing us the element that has been missing recently to create avalanches and increase the hazard. 

The other hazard we have talked about a lot recently has been difficult travel conditions with firm surfaces, frozen avalanche debris, and breakable crusts throughout the zone. As we continue to add more snow on top of these old surfaces, travel conditions have started to improve. Going forward, some areas may be stripped of recent light snow back down to these hazardous surfaces by the strong winds. Other areas could have avalanches run on firm crusts, putting them right back at the surface. Long story short, you need to continue to prepare for possibly firm and challenging travel conditions until we get a bit more snow.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

Regioni coperte