Lawinenlagebericht

Stevens Pass

Feb 15 – 16, 2017Northwest Avalanche Center
Auf der Karte ansehen
Archiviert · abgelaufen 10 years ago

Lawinengefahr

Fri
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich

Kernpunkte

With a fair amount of water in the upper snowpack, wet snow avalanches will maintain dangerous avalanches conditions Thursday. Wet slab avalanches are hard to predict and powerful due to the high water content. Allow the snowpack to stabilize, avoiding steeper slopes and any avalanche terrain where even a small wet avalanche could have serious consequences.   

Lawinenprobleme

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1
  • Wet Slabs

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

Detailed Forecast

After a mild and wet Wednesday night, a slow cooling trend is expected on Thursday with light to moderate showers. With a fair amount of water in the upper snowpack, wet snow avalanches will maintain dangerous avalanches conditions Thursday. Wet slab avalanches are hard to predict and powerful due to the high water content, so extra caution is advised. 

Loose wet snow avalanches may begin small but entrain deeper layers. Observations and tests for loose wet avalanches are more straightforward such as wet surface snow deeper than a few inches, rollerballs and natural loose wet avalanche activity.

Allow the snowpack to stabilize, avoiding steeper slopes and any avalanche terrain where even a small wet avalanche could have serious consequences. 

Shallow storm or wind slab may start to form in the near and above treeline elevation bands by Thursday afternoon, but will not be listed among the primary avalanche problems for Thursday. 

Snowpack Discussion

Weather and Snowpack

The 2/8 - 2/10 storm cycle left a strong rain or freezing rain crust with varying amounts of new snow received at the tail end of the cycle. Strong west winds on 2/10 exposed this firm and slick crust on windward aspects in many areas.  

High pressure Saturday to Tuesday brought increasing sunshine and warm temperatures. Temperatures reached the 40's and 50's in many areas of the Olympics and Cascades by Monday and Tuesday. This caused a lot of snowpack settlement, some small loose wet avalanche activity and a decreasing avalanche danger.

Another atmospheric river impacted the PNW on Wednesday. Heavy rain at high snow levels fell along the west slopes of the Cascades with localized freezing rain along the lower slopes of the Cascade Passes. 

Recent Observations

North

No observations on Wednesday.

Central

Alpental pro-patrol did not perform avalanche control Wednesday but reported a 1/2" freezing rain crust up to about mid-mountain with rain falling on the upper mountain. 

South

No observations on Wednesday.

Abgedeckte Regionen