Good morning. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Sunday, April 15th at 7am. This will serve as 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).
Today is our last day of 7-day a week advisories. We will be issuing updates on Wednesdays and Saturdays through April 30th (additional updates may be issued as conditions warrant). Checking the photos/observations page regularly will be the best place to find up to date information for the last two weeks of April. With that said, if you see an avalanche or have CNFAIC Staff snow/avalanche observations send them to us (by clicking on the “submit snow/avalanche observation” on the right side of the page) so we can post it!
Mark your calendars and join us for the first annual “Corn Harvest”event: April 22nd from 4-7pm at motorized lot in Turnagain. Free food, beacon park, etc., all provided by the Friends of the CNFAIC as an Avalanche Center Awareness day – see you there!! (Remember, it is not too late to become a Friends member and/or donate to help support the avalanche center operations).
A CONSIDERABLE danger exists in the mountains today and may persist through early this coming week. New snow and high winds at the upper elevations, along with rain at the lower, falling on a tenuous pack make for a variety of avalanche concerns. Wet avalanches below treeline and storm snow instabilities above treeline, on all aspects, warrant conservative travel and avoiding avalanche terrain is recommended. Essentially, there is a lot going on avalanche-wise and the mountains deserve respect.
Well, the sunshine could not last forever…but it sure was nice. The mountain snowpack, that was beginning to fall apart under the heat of the sun, is now forced to feel the effects of a springtime storm that moved in yesterday. Mid elevations (1500-3000ft) continue to be the most active with wet slab and glide avalanches occurring the past several days and running to valley bottoms.
This wet slab pulled out yesterday just above the Bertha Creek pull out on Turnagain Pass, east facing and around 1900ft.
Primary Concern – Wet Avalanches
Rain on snow from 1500ft and below will continue to trigger wet slab and wet loose avalanches at the mid and lower elevations on all aspects. Areas where wet avalanche activity is being seen daily are the east slopes of Seattle Ridge and Placer Valley.
Secondary concern – Storm Snow
We could see around a foot of heavy snow above treeline by the end of the day and this will bring new snow concerns back to the table. This includes wind slabs, soft slabs and point release avalanches. How well the new snow bonds to the older, variable surface is uncertain, especially at the higher elevations with lighter snow falling on a crust. As skies clear, beware of jumping onto slopes without evaluating the new/old interface as this could have unintended consequences. Additionally, when the sun hits the new snow for the first time (possibly Monday or Tuesday) it will likely initiate anCNFAIC Staff round of avalanche activity.
Above treeline – Persistent Slab
There is a layer of buried surface hoar that sits 10-20″ deep on northwest through northeast slopes above ~2500ft. New snow will add weight and stress which could cause it to fail naturally during the storm, or after the storm by the weight of a person or snowmachine. Depending on the amount of new snow that falls an avalanche breaking on this layer could be deep and dangerous.
Our week long stretch of sunny weather finally hit the road yesterday as a storm system began to nose in from the east with clouds, wind and precipitation hitting the Eastern Turnagain Arm by the early afternoon. The rain/snow line hovered near 1500ft and winds blew on the ridges from the east in the 20-30mph range.
Overnight, just over .6″ of water has been recorded, falling as rain below ~1500ft and wet snow above. Easterly winds have picked up and are sustained between 30-40mph with gusts 60mph. Today, between .5 and 1″ of water is forecast with the rain/snow line remaining around 1500ft. We could see around a foot of heavy snow above treeline by the end of the day. Easterly winds will continue in the 40-60mph range. It looks like this system will linger through Monday.
CNFAIC Weather Page and the NWS forecast
We will issue the next advisory Wednesday morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.