Good morning. This is Graham Predeger with the Chugach National Forest Avalanche Information Center on Tuesday, January 17th 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).
This Sunday January 22nd, CNFAIC forecasters will be hosting a FREE observer training day for snowmachiner’s! Please contact Graham at email@example.com for more details or to sign-up. Space is limited!
The avalanche danger today is LOW with pockets of MODERATE danger for loose snow sluffing and shallow wind slabs. Any unstable snow found today will likely be isolated to the upper 10-15″ of our snowpack and should prove quite manageable.
Our primary concern today will be loose snow sluffing generated by skiers or snowmachiners in steep terrain. Though usually manageable, entrained loose snow can ruin your day if you are knocked off your feet in exposed or complex terrain. Many people have been skiing this type of terrain over the last several days and will continue to do so. Expect and anticipate this loose snow and manage it accordingly when skiing or snowmachining on pitches greater than ~40 degrees.
A secondary concern today comes in the form of shallow wind slabs. The surface conditions now seem to be either blower powder or boiler plate wind slab. The blower powder that comes with sub-zero temperatures does not take much wind to transport and form a wind slab. Keep this in mind as surface conditions below your skis or sled change as you travel through the backcountry today.
Additionally, we had several reports of surface hoar formation in the Turnagain pass and Summit lake zones yesterday. It was quite prevalent and large (3-4mm) in the valley bottoms; losing size the closer you traveled toward ridge tops. This is likely due to the higher relative humidity (available atmospheric moisture) found in valley bottoms where fog persisted until yesterday afternoon in the Turnagain pass region. We will likely see continued surface hoar growth within our forecast area as long as this high pressure grips south-central AK. It’ll be a good idea to keep an eye on surface hoar distribution and it’s condition over the next several days before our next pulse of moisture.
Snowpack, weather and avalanche observations have really picked up over the last 7-10 days. Thanks to all who have taken the time to submit observations! The information we get from all of you is vital to producing an accurate daily advisory!
The Alaska region continues to be dominated by an impressive high pressure ridge today that will correspond to cold temperatures and clear skies throughout the forecast area. Expect winds to be light today at ridge tops (<12 mph) from the east.
Turnagain pass and Summit lake regions may again be shrouded in a fog bank this morning, however the persistent backcountry traveler will be rewarded with clear skies and (relatively) warmer temperatures once out of the valley bottoms. For example, the Portage valley weather station (10 feet) is reading -24 degrees at 5am this morning while the Sunburst weather station (3800 feet) is reading a balmy 6 degrees!
CNFAIC Weather Page and the NWS forecast
Kevin 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.