Boletín de aludes

Olympics

Northwest Avalanche Center
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Peligro de aludes

Sun
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 5 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Dangerous avalanche conditions will continue at upper elevations where you're likely to trigger a large avalanche on steep wind loaded slopes.  Steer around convex rollovers and unsupported slopes at lower elevations where you can trigger a storm slab avalanche. 

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2

    The same lee aspects that were loaded by new snow and strong southerly winds on Friday will see continued loading Friday night.  Avoid wind loaded slopes steeper than 35 degrees, especially open slopes above treeline where avalanches are likely to be deeper and more consquential.    

    You're most likely to encounter firmer wind affected snow on W-N-E aspects in the Hurricane Ridge area as winds scoured southerly aspects and ridgelines on Friday.  

    Identifying fresh cornices will help you determine which aspects were recently wind loaded. 

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    Steer around convex rollovers and steep unsupported slopes where you can trigger a storm slab avalanche in the new snow.  You can use small inconsequential test slopes to gauge the likelihood of triggering a storm slab avalanche before committing to steeper slopes.  Storm slabs may break on storm layers or down to the 3/3 crust.  The 3/3 crust should be anywhere from 12-18" below the surface in wind-sheltered areas. 

    If the sun pops out for an extended period on Saturday expect loose snow avalanches to release quickly on very steep sunny slopes and below rock outcroppings. Don't let these small avalanches catch you by surprise. 

     

    Ex: Human-triggered storm slab avalanche on an open slope below treeline.

Avalanche Discussion

NPS staff reported 16" of new snow Friday afternoon following whiteout conditions and moderate snowfall in the morning.  Snow levels had dropped to near 2000' by Friday afternoon following a frontal passage mid-day.   Snow showers and moderate S-SW winds should continue Friday night and taper back on Saturday.  

Prior to this storm, a new crust has formed on nearly all aspects (3/3 melt-freeze crust) following a few mild and sunny days midweek. The crust was thicker on sunny aspects that had gone through several melt-freeze cycles. Below the 3/3 crust, the upper snowpack is generally right-side up with increasing density the deeper you dig.  The 2/23 crust can still be found 12-16" deeper.  Weak snow (facets) were observed below this crust on Thursday but avalanches on this layer seem unlikely. The mid-Jan crust layer that's been so prominent in the Cascades can still be found in the Hurricane Ridge area albeit at much shallower depths; ~4 ft below the surface.  Avalanches down to this layer have not been observed in the Hurricane Ridge area in over a month but it's still worth tracking as we wait to see what March has in store for us.  

The snowpack is quite deep and healthy for this time of year, 130% of normal as of March 1st. 

Make sure to check out the Conditions blog for more info about the very large avalanches that have released throughout the central and southern Cascades over the past two weeks.  There are some impressive photos of a few of these monster slides included in the media reel below.  

2020-21 Forecast Schedule: Avalanche danger ratings will be issued for the Olympics every Friday through Sunday and during mid-week holidays. During the week when the Hurricane Ridge road is closed, forecast information will be updated daily to include expected conditions and relevant travel advice under the No Rating label.

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.

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