Two feet of new snow and strong winds (up to 96mph) over the last 24 hours have created dangerous avalanche conditions for our entire region (Girdwood, Turnagain Pass, Portage, Placer Valley and Summit Lake.) Strong Easterly winds 20-40mph will continue through late afternoon and 5-10” of additional snow is expected today. Natural avalanches 2-4+ feet deep are likely and human triggered avalanches are very likely. Precipitation has remained snow to sea level, and cold snow means avalanches could run faster and farther than expected. Avoiding avalanche terrain is necessary today, which includes staying far away from runout zones of larger slopes above. Later today as winds decrease and snow stops falling be careful not to get tempted into steeper terrain. This new snow has fallen on hard surfaces and weak snow below and bonding will be poor. An avalanche from above could run into valley bottoms, especially in places like Seattle Ridge, Portage Lake and Placer Valley.
Storm totals as of 6am:
Types of storm snow avalanches that are expected today:
– Wind slabs: Slabs up to 2-4 feet thick due to strong winds loading leeward aspects and terrain features
– Storm slabs: Soft slabs (2 feet deep) are expected in areas out of the wind due to rapid loading and poor bonding with the old surface
– Cornice falls: Cornice fall could trigger a wind slab or storm slab below
AKDOT snowstake at Turnagain Pass is showing around 2 feet of new snow in the last 24 hours.
Yesterday at the beginning of the storm observers experienced strong winds even in the mid elevations. Photo taken at 12pm (3/8/18) at Sunburst around 1800′.
A storm related avalanche could ’step down’ into a deeper weak layer causing a very large avalanche to send debris well into valley bottoms. Another reason to let the mountains sit as the storm moves out of our area. Areas on the South end of Turnagain Pass and the Summit Lake area are most suspect for having deeper weak layers release.
Several widespread persistent weak layers exist within our snowpack region wide including buried surface hoar and facets 1-2′ below the old surface. Don’t forget we haven’t had a storm like this in months. Lots of uncertainty exists around how our old weak snowpack will adjust to its new load.
Over the last 24 hours 18-26 inches of snow has fallen across our forecast zone. Yesterday Easterly winds increased into the 60’s mph in the afternoon with gusts into the 90’s mph. Overnight Easterly winds decreased into 20-40mph range. Temperatures at 3000′ have been in the low 20F’s and temperatures at sea level have been around 33F.
Today another 5-10 inches of snow (.5 € SWE) is expected through mid afternoon and scattered snow showers this evening. Southeast winds will continue to be strong (20-45mph) and decrease to 15-25mph by late-afternoon. Temperatures at 3000′ will be in the mid 20F’s and temperatures at sea level may increase into the mid 30F’s, but precipitation is expected to remain as snow at sea level.
Snow showers are in the forecast through the weekend, but precipitation amounts remain uncertain. For Saturday winds are expected to be light from the East and temperatures in the upper elevations will be in the low to mid 20F’s and temps at sea level will be in the upper 20F’s to low 30F’s.
*Temperatures at Center Ridge weather station have been reporting warmer temps compared with other weather stations at this same elevation band. There have been some issues with this temperatures sensor this winter.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||*31||26||1.0||93|
|Summit Lake (1400′)||28||14||0.5||44|
|Alyeska Mid (1700′)||27||18||1.36||77|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||23||E||26||62|
|12/06/19||Turnagain||Avalanche: Sunburst||Billy Finley|
|12/04/19||Turnagain||Observation: Sunburst||A.Johnston-Bloom/ W.Wagner/ R.Van Luit Forecaster|
|12/03/19||Turnagain||Observation: Hippy Bowl||Nick Langowski|
|12/01/19||Turnagain||Observation: Tincan, All elevations||Eric Roberts|
|12/01/19||Turnagain||Observation: Tincan||Andy Moderow|
|11/30/19||Turnagain||Observation: Tincan Treeline Plateau/ Common Bowl/ Ridge||Eric Roberts|
|11/29/19||Turnagain||Observation: Sunburst Ob #2||Aleph Johnston-Bloom Forecaster|
|11/29/19||Turnagain||Observation: Sunburst Ob #1||Aleph Johnston-Bloom Forecaster|
|11/27/19||Turnagain||Observation: Tincan||Aleph Johnston-Bloom Forecaster|
|11/25/19||Turnagain||Observation: Sunnyside||Graham Predeger Forecaster|
Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: firstname.lastname@example.org
|Area||Status||Weather & Riding Conditions|
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