November 15 UPDATE
Wind and snow return to Southcentral
24 hour predicted snow totals through tomorrow morning. Graphic courtesy of NWS Anchorage, 11.15.2023
We’re looking at another round of active weather, but this time it is looking like wind will be the biggest player. After Monday’s snow and outflow winds, we had a break in the weather yesterday with clear skies and calm winds. That has already changed, with ridgetop weather stations showing sustained easterly winds at 15-25 mph with gusts around 45 mph since yesterday around 9 pm. Those southeasterly winds are expected to continue to increase today, with extended periods of wind speeds averaging 25-40 mph and gusts getting up around 60 mph in Turnagain Pass, and even higher in the Front Range. Along with these strong winds, we are expecting another round of snow, with 4-8″ through most of the advisory area, and 10-15″ possible in the Portage and Placer Valleys. You guessed it- avalanche danger is on the rise.
The primary concern today is straightforward. We have already seen nearly 12 hours of strong winds, with more on the way. Along with another dose of new snow, expect to find dangerous surface conditions. The odds are favorable that a person will be able to trigger a wind slab avalanche 1-2′ deep today. Given the strength of these winds, look for dangerous conditions even at and below treeline elevations. Avoid steep slopes with stiffer snow at the surface, and be especially cautious below ridgelines, around convex rolls and cross-loaded gullies.
The second concern involves weak layers buried deeper in the snowpack. While it may be less likely to trigger an avalanche on one of these layers, they will be bigger with more severe consequences. Prior to Monday’s storm, we saw a widespread layer of surface hoar develop (details in this observation). Although we were unable to find signs of that layer being reactive yesterday on Seattle Ridge (details), that layer may still be lurking just below the surface and may increase the chances of triggering a large avalanche today. In addition to that buried surface hoar layer, we have already seen avalanches fail on the ground at higher elevations (details from Goldpan last Saturday). This problem exists on slopes that had snow prior to the 11/9 storm, which means the most dangerous terrain is steep, rocky slopes above around 3500′.
CHUGACH STATE PARK:
The strongest winds today will most likely be hitting the Chugach Front Range, with ridgetop wind speeds averaging 25-45 mph and gusting to 70 mph. Observers have been reporting signs of unstable snow for the past week (See Mary’s ob from the South Fork yesterday for the latest), which means it is likely we can see avalanches failing deeper in the snowpack as well as the fresh wind slabs we are expecting today.
Windblown snow on Seattle Ridge from Monday afternoon’s winds. Coverage is looking good up there, and the Forest is currently working on getting the paperwork finished to get the motorized areas open. 11.14.2023
Chugach NF Avalanche Center – early season operations:
- This will be our last early season Conditions Update. We will begin issuing daily avalanche advisories this Saturday, November 18.
**PLEASE, send us your reports if you head into the mountains. It’s easy – even just a photo is greatly appreciated.
Avalanche rescue gear and communications:
- Is your rescue gear working properly?
- Beacons (avalanche transceivers) – fresh batteries
- Probes – able to assemble properly with no weak points in the cable
- Shovels – not damaged and is a true avalanche shovel
- Airbags – charged, working properly, and tested
- InReach up to date and associated with the correct emergency contacts
POSTPONED: Southcentral Alaska Avalanche Workshop – now Nov 17, 9:00am to 4:30pm
- Alaska’s Annual snow science workshop (SAAW) is all set to happen this Friday, November 17. Visit akavalancheworkshop.org for the most up to date information. This event is geared for both snow professionals and public backcountry users alike. If you are a snow/avalanche geek, this is the event for you!
Also POSTPONED- MSP Ski Film!
Due to ASD closures, this fundraiser has been postponed to Friday, Nov 17th. If you have already bought tickets for this event, please check your email for more information.
- MatchStick Productions – “The Land of Giants” – Trailer HERE.
- Showing at the West Anchorage High School Auditorium.
Tickets HERE ($20 in advance and $25 at the door).