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-- ARCHIVED ADVISORY --
All advisories expire after 24 hours from the posting date/time. Summit Lake advisories are issued on Saturdays.

Sunday, February 19th 2012

Created: Feb 19th 6:18 am
Updated: Feb 19th 6:59 am

Good morning backcountry travelers, this is Adam Clark with the Chugach National Forest Avalanche Information Center on Sunday February 19th at 7 am. This will serve as a general backcountry avalanche advisory issued for Summit Lake as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas). This advisory expires 24 in hours after posting.


BOTTOM LINE
At treeline and above treeline, especially on wind loaded terrain, human-triggered avalanches are likely and natural avalanches are possible. In these areas dangerous avalanche conditions exist. Below treeline, human-triggered avalanches are possible, while naturally-triggered avalanches are unlikely. At these lower elevations there will still be heightened avalanche conditions on certain terrain features such as steep gullies and convex rollovers.

AVALANCHE DISCUSSION
It is amazing how driving a few miles down the Seward Highway can totally change the avalanche picture. While Turnagain Pass was hit with storm after storm, smothering the slopes with feet of snow, the Summit Lake region only saw 6-12 inches of new snow over the past week. While the snowfall may have been lacking, the winds kept up, with gusts in the 30 to 50 miles per hour range each day over the past 7 days.

Thus, the primary avalanche concern for the Summit Lake region are wind slabs located in exposed terrain starting at treeline. The wind damage seems to be fairly widespread with reports mentioning breakable wind crusts and stiffer slabs well below many of the ridge crests. During my ski tours this past week I was able to find these reactive slabs if we made it high enough up the mountain. But on other days, we did not even go above treeline due to the strong winds and active loading. Conditions seemed to worsen midway through last week, and on Friday we saw evidence of several 1 to 2 day old natural slab avalanches which had released in this higher elevation terrain. Travel today up in the alpine zones will require conservative decision-making to ensure you do not end up triggering some patch of unstable wind slab.

Below tree line there is better news. The snow is settling and is more stable overall thanks to warmer temperatures and shelter from the wind. Plus the skiing has been great. Something to look out for however is a layer of near-surface facets we have found on various aspects about 20 inches down in the snowpack. This noticeably weaker layer has not been super reactive in my snowpits, but I am still cautious of it. This was the weak layer reported to have caused the avalanche last week on Raven Ridge. While the danger may be less at lower elevations today, you will still need to evaluate your terrain and snowpack carefully. To get a head start on this task, you can check out this nice full pit profile taken yesterday on Tenderfoot Ridge. It can be found in our observations section HERE.


WEATHER ROUNDUP

Summit Lake Snotel (@ 6:00 a.m.): Temperature: 24 F, Past 24hrs: High 30 Low 12, Snow Depth 58"
Fresno Weather Station (@ 6:00 a.m.): Temperature: 20F, Winds NNE 18 mph Gust to 25 mph.


Over the past 24 hours about 1 inch of snow has fallen at the Summit Lake Snotel. Up on Fresno Ridge, NNE winds have been blowing in the 15 to 20 mph range with gusts 20 to 35 mph. The forecast is calling for light snow with 1-4 inches possible today and 2-4 tonight.

We also have a new Weather History link on our webpage. Here you can access weather charts for the Summit Lake area along with weather history information for Turnagain Pass.

Zone Forecast: Western Prince William Sound Mobile Weather Information

500 AM AKST SUN FEB 19 2012

.TODAY...SNOW SHOWERS. SNOW ACCUMULATION 1 TO 3 INCHES. HIGHS
IN THE UPPER 20S TO MID 30S. NORTH TO EAST WIND 5 TO 20 MPH.
GUSTS TO 30 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.
.TONIGHT...SNOW SHOWERS. SNOW ACCUMULATION 1 TO 3 INCHES. LOWS
IN THE LOWER 20S TO LOWER 30S. NORTH TO EAST WIND TO 15 MPH
EXCEPT EAST 15 TO 25 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.
.WASHINGTONS BIRTHDAY...SNOW. SNOW ACCUMULATION 2 TO 5 INCHES.
HIGHS IN THE UPPER 20S TO MID 30S. NORTH TO EAST WIND 15 TO 30 MPH.
.MONDAY NIGHT...SNOW AND RAIN LIKELY. LOWS IN THE MID 20S TO
LOWER 30S. NORTH TO EAST WIND 15 TO 30 MPH BECOMING NORTH TO
WEST 15 MPH AFTER MIDNIGHT.
.TUESDAY...SNOW AND RAIN LIKELY. HIGHS IN THE UPPER 20S TO
MID 30S. VARIABLE WIND TO 10 MPH.


Always remember that safe backcountry travel requires training and experience. You control your own risk by choosing where, when, and how you travel.

Thanks for checking today’s avalanche conditions. The next posting for Summit Lake area will be from Alex at 7am Saturday February 25th. If you have information that you would like to share hit the public observations link and submit it or call Alex at (907)288-7710.

Weather and Riding Updates for CNF

(Updated: Feb 21, 2012 )
AREA
RIDING STATUS
WEATHER AND RIDING CONDITIONS
GLACIER DISTRICT
Johnson Pass
Open
Motorized trail follows the wagon road, South of the summer route (ski trail). Follow the signs or you will likely enter areas closed to motorized use.
Placer River
Open
Open water leads do exist.
Skookum Drainage
Open
Turnagain Pass
Open
Twentymile
Open
Park at the Portage rail depot and cross the RR tracks at the designated spot ONLY! Please follow bamboo poles from the parking area.
SEWARD DISTRICT
Carter Lake
Open
 2/11/2012 34" at parking lot.
Lost Lake Trail
Open
 2/11/2012 46" of snow in the trees start of trail, No Ice on trail Bumpy!
Primrose Trail
Open
 2/11/2012 32" of snow at parking area.
Resurrection Pass Trail
Open
 2/11/2012 At Res south (West Juneau Rd) 26" of snow
Snug Harbor
Open
 2/11/2012 62" at snowtel site. Very icy road..Rain/snow
South Fork Snow River Corridor
Open
2/11/2012 52" of snow at start of trail.
Summit Lake
Open
2/11/2012 60 inches of snow at summit Lake.

General Snow Conditions for the Turnagain Area - Updated As Necessary

Date
Snow Condition Update

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:
The Friends of the Chugach National Forest Avalanche Information Center

Thanks to our Sponsors:
and to our Members!

View an older advisory (Summit):
Prior Years

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Mar 10th, 2012 -- Mar 12th, 2012
  Level 1 Backcountry Avalanche Hazard evaluation and rescue
3 days. $345 per person Hatcher Pass Alaska Avalanche School More Info: www.alaskaavalanche.org/Schedule.html
Mar 10th, 2012
9:00 AM - 1:00 PM
  Observer Training Day (non-motorized)
Join a CNFAIC avalanche forecaster for a day in the field! The purpose of these observer training sessions is to teach and encourage users how to submit quality snowpack, weather and avalanche observations for inclusion into daily avalanche bulletins. This session is open to Skiers or split-boarders with intermediate or advanced travel skills. Sign up by emailing Kevin Wright at kevin@chugachavalanche.org Space is limited.
Mar 16th, 2012 -- Mar 18th, 2012
  Level 1 Backcountry Avalanche Hazard evaluation and rescue
3 days. $345 per person Girdwood and Turnagain Arm Alaska Avalanche School More Info: www.alaskaavalanche.org/Schedule.html