CNFAIC LogoCNFAIC Logo

Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Tuesday, March 24th 2015
Created: Mar 24th 6:07 am
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
0 NO RATING Below Treeline / Below 1,000'
 Show the Complete North American Avalanche Danger Scale
Special Announcement
  • There will be intermittent traffic delays on the Seward Highway for avalanche hazard reduction work today between Girdwood and Bird (MP96-100). Motorists should expect delays of up to 45 minutes between 10:00AM and 12:00 noon. AKDOT&PF Avalanche Program crews are improving existing shot points. 

The Bottom Line

A generally LOW avalanche danger exists in the mountains around Turnagain Pass.

*Low does not mean no and a few things to keep in mind today are: An increase in Easterly winds may be enough to form shallow fresh wind slabs in isolated areas; this will be easy to see. Hard to see are areas where 1-2 foot slabs are sitting on weak faceted snow and though an outlier, may still be possible for a person to trigger. Keeping with safe travel practices is key - exposing one person at a time and having escape routes planned.


Primary Concern

Today will be our last bout of sunshine before a multi-day storm cycle moves in tomorrow. Winds have already increased from the East on the ridgelines and are expected to be in the moderate (15-20mph) range through the day. There is very little snow available for transport considering a sun crust sits on the surface on all but Northerly aspects. However, with the complex flow patterns often seen, there could be areas where the loose settled snow from shady zones is blown into fresh wind slabs. Any new wind slab will likely be shallow, easy to identify, but also easy to trigger - especially if it sits on a slick crust.

Photo: The Easterly face of Lynx creek is covered with a shiny sun crust - hence, little to no snow available for transport with the Easterly winds in this area today. (Lynx is the drainage one looks at while driving South through Turnagain Pass).


Secondary Concern

It's been just over a week since a layer of faceted snow was covered by a 2-3' slab (post St. Patty's Day storms 3/16 and 3/19) and widespread avalanche activity ensued. We have been talking about this problem extensively and the variable nature of where it exists and where it does not. In short, triggering a persistent slab is becoming more and more unlikely because 1) many slopes have either already avalanched, 2) the facets were blown away before the storm or 3) the slab/weak layer has adjusted. 

That said: there is still a remote chance a person could trigger a slab up to 2' thick that fails in weak faceted snow. Shaded aspects with no surface crust are the most suspect. Safe travel practices are encouraged - expose only one person at a time on a slope and have an escape route planned.


Additional Concern

Cornices:

Just because the winds will keep the sun from affecting the snow in many areas today, steering well clear of cornices is always a good idea. Cornice crevasses are also likely to be found; this is where the cornice pulls away from the ridge underneath and creates a crack.

Wet Avalanches:

Slopes with a Southerly tilt that are sheltered from today's winds may warm enough to soften sun crusts and allow for human triggered wet loose avalanches. As is the norm, if you find yourself in boot-top, wet and unsupportable snow, it's time to move to a different aspect. 

South facing slopes have seen the full effects of the sun recently! Photo: Breakable crust on Corn Biscuit


Mountain Weather

Yesterday was one of those brilliant blue-bird days in Alaska. Temperatures were warm, in the 30's F, and winds were calm with an occasional light breeze on the ridgetops from the East.

We have one more sunny day on tap before stormy weather tomorrow. Ridgetops winds have just started to kick up from the East this morning and will remain in the 15-20mph range. Temperatures should stay warm at the parking lots, ~35F, yet stay cooler on the ridgelines, ~25F.

Looking forward to Wednesday and later in the week, a series of shortwaves (imbedded disturbances) will spin around a large low-pressure South of Kodiak bringing a several day storm cycle to Southcentral. This pattern looks to remain - more or less - through Sunday. The storms will be warm, but at this point not terribly warm with a rain/snow line hovering around 1,500'. Accumulations for the first pulse of moisture (Wednesday through Thursday) are looking to be in the 1" H20 range; this equates to around a foot of snow up high. Stay tuned!

 

PRECIPITATION 24-hour data (6am - 6am)

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 36   0 55 
Summit Lake (1400') 29    0  0 12 
Alyeska Mid (1700') 35   0 32 

 

RIDGETOP 24-hour data (6am - 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 27  NE  21 
Seattle Ridge(2400') 28  n/a 27 

This is 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).

Winter snowmachine use open/closed status and riding conditions updates

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: Mar 28, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: OpenPlease park on road in and leave the turnaround (near outhouse) open for trailers to turn around.
Placer River: OpenPlacer remains open but SKOOKUM DRAINAGE will close to motorized use on April 1st.
Skookum Drainage: OpenSKOOKUM DRAINAGE CLOSES TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: Open
Seward District
Carter Lake: Open
Lost Lake Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Primrose Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Resurrection Pass Trail: ClosedClosed for 2016/17 winter season. This is a non-motorized season. This alternates every other year and will open again during the 2017/18 winter.
Snug Harbor: Open
South Fork Snow River Corridor: Open
Summit Lake: Open

Subscribe to the Turnagain Area Avalanche Advisory:

The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur. This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.


USFS SNOW AND AVALANCHE HOTLINE (907) 754-2369
If you have comments or questions regarding CNFAIC operations or winter recreation management, please email staff@chugachavalanche.org
© 2017 Chugach National Forest Avalanche Information Center. All rights reserved.
FCNFAIC