Turnagain Pass RSS

Archives
ARCHIVED - Forecasts expire after 24 hours.
Issued
Mon, March 10th, 2014 - 7:00AM
Expires
Tue, March 11th, 2014 - 7:00AM
Forecaster
John Fitzgerald
Avalanche risk The Bottom Line

The avalanche hazard will be on a quick rise today.   This morning the hazard is LOW at all elevations.   New snow and wind will bump the hazard to CONSIDERABLE by the end of the day, as a winter storm impacts the area.   Snowfall amounts in the 10 € to 14 € range will create slabs that will be very sensitive to human triggers and could release naturally.

Mon, March 10th, 2014
Alpine
Above 2,500'
3 - Considerable
Avalanche risk
Treeline
1,000'-2,500'
3 - Considerable
Avalanche risk
Below Treeline
Below 1,000'
3 - Considerable
Avalanche risk
0 - No Rating
1 - Low
2 - Moderate
3 - Considerable
4 - High
5 - Extreme
Avalanche risk Avalanche risk Avalanche risk Avalanche risk Avalanche risk
Travel Advice Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential. Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
Likelihood of Avalanches Natural and human-triggered avalanches unlikely. Natural avalanches unlikely; human-triggered avalanches possible. Natural avalanches possible; human-triggered avalanches likely. Natural avalanches likely; human-triggered avalanches very likely. Natural and human-triggered avalanches certain.
Avalanche Size and Distribution Small avalanches in isolated areas or extreme terrain. Small avalanches in specific areas; or large avalanches in isolated areas. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. Large avalanches in many areas; or very large avalanches in specific areas. Very large avalanches in many areas.
Avalanche Problem 1
  • Storm Slabs
    Storm Slabs
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
More info at Avalanche.org

Over the past several days we have been mapping the snow surface.  A consistent theme around the forecast zone is a thin layer of weak snow sitting on a crust.  This set up by itself is not a concern.  Today that all changes as a slab will be sitting on this weak interface by the end of the day.

Snowfall amounts (and intensity) on their own will be enough to create unstable conditions.  In areas where this slab/weak layer/crust combo exists, the snow will be very unstable.  Avalanche terrain at all elevations will become more prone to activity as the new snow accumulates.  As snowfall amounts begin pushing past the 6-8” range, it will become more likely for slabs and loose snow avalanches to occur naturally.  Be on the lookout for obvious signs of unstable snow: recent avalanches, shooting cracks, & collapsing/whoompfing.  If you start seeing any of these signs, it is time to scale back on terrain choices.

In favored locations and wind loaded areas slabs could grow into the 2 foot range.  All slopes above 35 degrees or in the runout of terrain above should be avoided as slabs increase in depth throughout the day.

Weather
Mon, March 10th, 2014

In the past 24 hours ridgetop temperatures have averaged in the high teens F.   Winds have picked up overnight and are currently 24 mph at the Sunburst station, 17 mph at Seattle Ridge, and 22mph at Alyeska (Max’s) out of the East.   Clouds moved in overnight as the leading edge of a storm made its way into the area.

Winter part 3 has arrived!

A strong Low pressure system South of the Alaska Peninsula is moving towards Southcentral AK.   Snow has begun to fall this morning.   Expect snowfall intensities to pick up throughout the course of the day.   Accumulations of up to up to 14 € (.9″ H20) can be expected by sunset (7:49pm).   Ridgetop winds will be moderate to strong out of the East averaging 20-30 mph with gusts to 70 mph.   Temperatures at 1,000′ will be in the high 20s to low 30s F.

Snow, which will be heavy at times, will continue overnight and should taper off by Tuesday evening.   Another Low pressure system coming from the Southwest will move into the area on Wednesday, bringing another round of snow.   An active weather pattern will continue through the week as a series of Lows track through the area.

Observations
Recent Observations for Turnagain Pass
Date Region Location
05/13/24 Turnagain Observation: Eddie’s, Sunburst, Seattle, Cornbiscuit, Pete’s South
05/13/24 Turnagain Observation: Turnagain Pass non-motorized side
05/12/24 Turnagain Observation: Warm up Bowl
05/07/24 Turnagain Observation: Turnagain Pass Wet Slabs
04/29/24 Turnagain Avalanche: Turnagain aerial obs
04/27/24 Turnagain Observation: Johnson Pass
04/23/24 Turnagain Observation: Turnagain Sunny Side
04/21/24 Turnagain Observation: Bertha Creek
04/20/24 Turnagain Avalanche: Spokane Creek
04/16/24 Turnagain Observation: Cornbiscuit
Riding Areas

The riding areas page has moved. Please click here & update your bookmarks.


Subscribe to Turnagain Pass
Avalanche Forecast by Email

This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area. This advisory does not apply to highways, railroads or operating ski areas.