Fri, February 21, 2014 Turnagain Pass Avalanche Forecast

Fri, February 21st, 2014

Alpine

Above 2,500'

2 - Moderate

Treeline

1,000'-2,500'

2 - Moderate

Below Treeline

Below 1,000'

2 - Moderate

0 - No Rating

1 - Low

2 - Moderate

3 - Considerable

4 - High

5 - Extreme


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

Persistent Slabs

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

More info at Avalanche.org

A layer of weak snow sitting between the January crust and the February snow has the potential to cause problems today. While this layer has become less reactive over the last week, it is still not trustworthy. The nature of a persistent weak layer is that it sticks around for a long time. Unlike storm related instabilities, a layer like this does not heal quickly. Rather, it lurks below the surface, waiting for the right trigger.

Areas where you would be most likely to activate this weak layer today are on slopes greater than 35 degrees, steep rollovers, and previously wind loaded pockets. Sunshine and excellent riding conditions have the potential to lure people onto bigger and steeper terrain. Don’t let a lack of activity on lower angle slopes allow you to let your guard down. It is much easier to manage this problem with conservative terrain choices than trying to outsmart this complex instability.

Avalanche Problem 2

Dry Loose

Dry Loose

Dry Loose avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

More info at Avalanche.org

On steep sunlit aspects loose snow avalanches will be easy to trigger today. Expect these to be relatively low volume. Managing this problem requires awareness of snow moving around you and the ability to get out of its way. Loose snow sluffs have the potential to knock over skiers and snowboarders (less of an issue for snowachiners). This issue becomes more serious when terrain traps (e.g. trees, gullies, cliff bands) are below.

Weather

Fri, February 21st, 2014

In the past 24 hours no new precipitation has fallen. Ridgetop winds have been light out of a variety of directions averaging 5mph with a max gust of 21mph. Temperatures at 3,800′ have averaged 9 degrees F.

Today expect mostly clear skies in the morning with clouds developing throughout the day. Temperatures will climb into the low 20s F at 1,000 feet. Ridgetop winds will be out of the Southeast at 15 mph.

A strengthening area of high pressure to the East and North of us is keeping several Low pressure systems at bay, limiting the chance for precipitation over the next several days.

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
04/16/24	Turnagain	Observation: Cornbiscuit	Krueger / Matthys Forecaster
04/15/24	Turnagain	Observation: Taylor Pass	John Sykes Forecaster
04/15/24	Turnagain	Observation: Seward Highway – Tern Lake to Portage	Joel Curtis
04/14/24	Turnagain	Observation: Sunburst	T. Olsen-Lund, R. Sullivan I. Adams
04/14/24	Turnagain	Observation: Turnagain Pass Snomo	K. Gallaher
04/13/24	Turnagain	Observation: Spokane Creek	Everet Megli
04/11/24	Turnagain	Observation: Tincan	John Sykes Forecaster
04/10/24	Turnagain	Avalanche: Seattle Ridge	Schauer/ Keeler Forecaster
04/10/24	Turnagain	Observation: Cornbiscuit South Face	Todd Kelsey
04/10/24	Turnagain	Avalanche: Tincan	N. Dumont J. Carlberg

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