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Current Advisory (Summit Lake Area)

Friday, March 12th 2010

Created: Mar 12th 6:41 am
Updated: Mar 12th 6:45 am

Good morning backcountry travelers this is Jon Gellings with the Chugach National Forest Avalanche Information Center on Friday March 12th 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 is a new addition to the CNFAIC program, and will only be updated on Fridays and Saturdays for the time being, and all advisories expire 24 hours after being posted. Expired advisories can be accessed by looking through the advisory archive on the right. Backcountry travelers can analyze the weather trend between the expired advisory date and the current date to make pertinent avalanche terrain decisions.**

AVALANCHE DISCUSSION

Based on recent observations and data, natural avalanches are unlikely and human triggered avalanches are possible. Small avalanches in specific areas or large avalanches in isolated areas are expected today. There are heightened avalanche conditions on specific terrain features. Evaluate the snow and terrain carefully, and identify features of concern.

We toured up Tri-tip Mountain yesterday, and were wondering how the new snow was setting up near the starting zones. There is a density change between the 2 most recent snow events, which was created by a dip in temperatures on March 7th. The snow that fell above this layer came in 15 degrees warmer with very strong winds, but still managed to stay quite soft where it was transported to. The overlying snow ranges from 6-8” deep soft-slabs in deposition zones to 2-3” hard-slabs on wind affected terrain. Several of these soft-slabs naturally avalanched during our most recent snow and wind event, but they could still hold enough energy today in wind-loaded areas steeper than 38 degrees. This instability was not reactive to 8 snowboarders and skiers that rode from the top of the ridgeline to the lake yesterday.

We dug our first pit at 2500’, and another at 3500’ which yielded similar results. We had easy breaks with moderate energy (2x CTE3Q2, CTE5Q2), underneath this newest snow and very hard breaks with low energy (3x CT30++Q3) on the melt-freeze crust 2-3’ down from 2 weeks ago. We did not hear any whumpfs or feel any collapses, but did see up to 10’ shooting cracks in isolated snow on ridgeline slopes greater than 35 degrees. A test slope indicated that fractures would possibly start propagating on wind loaded slopes over 45 degrees. A cornice that was broken did not show any results of instability further down the slope, and broke up to a foot thick. A quick pit on the first Northern chute showed similar results as on the Western aspect.

WEATHER ROUNDUP

Weekly Roundup
Since our last advisory, we watched temperatures drop down to the single digits, rise back up to the mid-20s, and decrease to -12 two days ago at Summit Creek. The Fresno Ridge station showed similar trends, but not to the extent as the lower station was. Winds have gusted to 75 mph from the South East, and have currently backed off to gusts in the lower 20s. 9 inches of new snow fell on March 8th, and was accompanied by the gusts to 75 mph.

Hindcast (Last 24 hours)

3440’ – Fresno Wx Station-
Current temp is -1 (4 degrees warmer than yesterday), and winds have been calm out of the South West with gusts in the single digits and teens up to 23 mph.

1400’ – Summit Lake Wx Station-
Current temp is -8 (5 degrees colder than yesterday), with 0 inches of snow over the past 24 hrs.

Nowcast

Temperatures are currently quite cold, but are supposed to warm up by this afternoon. The possibility of partial clearing today could allow the sun to start affecting South facing slopes above 30 degrees again, so keep this in mind while travelling if the clouds break. The snow depth has settled 2” since yesterday down to the current depth of 50”. Winds are currently from many directions, but mainly from the South West blowing lightly. There is not much precipitation showing up on the Middleton and Kenai radars, so Summit will not likely receive new snow today. Today’s weather will not contribute to the avalanche hazard, but expect it to once the new 967 mb Low pressure system comes into the area overnight or tomorrow.

Forecast

WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKST FRI MAR 12 2010
.TODAY...MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. HIGHS 15 TO
25. VARIABLE WIND TO 10 MPH. NEAR WHITTIER...WEST WIND 10 TO 20 MPH.
.TONIGHT...MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. LOWS 10 TO
20 ABOVE. VARIABLE WIND TO 10 MPH.
.SATURDAY...SNOW LIKELY. SNOW ACCUMULATION UP TO 2 INCHES. HIGHS
AROUND 30. VARIABLE WIND 10 MPH EXCEPT NORTH 15 TO 25 MPH NEAR
SEWARD.
.SATURDAY NIGHT...SNOW LIKELY. LOWS IN THE 20S. NORTH WIND 10 TO
15 MPH EXCEPT NORTH 20 TO 30 MPH NEAR SEWARD.
.SUNDAY...SNOW LIKELY. HIGHS IN THE 30S. NORTHEAST WIND 10 TO
15 MPH EXCEPT NORTH 15 TO 25 MPH NEAR SEWARD.
.SUNDAY NIGHT...SNOW LIKELY. LOWS IN THE UPPER 20S TO LOWER 30S..

Temperature / Precipitation

SEWARD 19 14 31 / 40 40 70
GIRDWOOD 26 14 29 / 30 30 40

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 advisory. The next one will be posted tomorrow on Saturday March 13th.

Weather and Riding Updates for CNF

(Updated: Mar 10, 2010 )
AREA
RIDING STATUS
WEATHER AND RIDING CONDITIONS
GLACIER DISTRICT
Girdwood
Open
State owned land is OPEN for snowmobiles and their generally allowed uses. Muni and USFS land in the upper valley is closed to snowmachining.
Johnson Pass
Open
as of 03-04-2010 three day snow total - 16"
Placer River
Open
OPEN! Wednesday 3/10/2010
Skookum Drainage
Open
Turnagain Pass
Open
as of 03-04-2010 three day snow total - 24"
Twentymile
Closed
3/10/2010. We will take a closer look for a potential opening.
SEWARD DISTRICT
Carter Lake
Open
03/08-09: 18" new snow at trailhead, 30" new snow at Carter Lake
Lost Lake Trail
Open
03/08-09: 24" new snow at trailhead
Primrose Trail
Open
03/08-09: 8" new snow at trailhead
Resurrection Pass Trail
Open
03/08-09: 18" new snow in Cooper Landing area & on south part of trail
Snug Harbor
Open
03/08-09: 12" new snow at parking area, 64" total
South Fork Snow River Corridor
Open
03/08-09: Open water. 18" new snow.
Summit Lake
Open
03/08-09: 12" new snow, 56" total

General Snow Conditions for the Turnagain Area - Updated As Necessary

Date
Snow Condition Update
Tuesday, March 9th 2010Parking Lot Snowstake Measurements:
Eddies: 9" new
Motorized Lot: 9" new
Sunburst Lot: 7" new
Johnson Pass North Lot: 19" storm total *we were unable to check this stake on 3/8
Monday, March 8th 2010Parking Lot Snow Stake Measurements:
Eddies Lot: 22" new
Motorized Lot: 22" new
Sunburst: 15" new
Johnson Pass North Trailhead: unable to access parking lot

Ingram Creek: 11" new mixed with some rain
Placer Main/Overflow: 12-16" new mixed with some rain
20 Mile: 14" new mixed with some rain
Saturday, March 6th 2010Parking Lot Snow Stake Measurements (48 hour):
Eddies Lot: 12" new snow
Motorized Lot: 17" new snow
Sunburst Lot: 7" new snow
Johnson Pass North: 8" new snow
Friday, March 5th 2010Three day snow fall totals as of 03-04-2010:
Eddies-20"
Turnagain Motorized lot - 24"
Sunburst - 18"
Johnson - 16"
Lost Lake TH - 10" Lost Lake Trail is improving but still needs more snow cover before it can handle lots of snowmachine use.
Divide - 16"
Primrose - 10"
Moose Pass area - 8"
Summit - 6"
Cooper Landing - 4"
Wednesday, March 3rd 2010Parking Lot Snow Stake Measurements:
Eddies Lot: 13"
Motorized Lot: 14"
Sunburst: 6"
Johnson Pass North Trailhead: 6"
Tuesday, March 2nd 2010Parking Lot Snow Stake Measurements:
Eddies Lot: 3"
Motorized Lot: 4"
Sunburst Lot: 2"
Johnson Pass North Trailhead: trace
Sunday, February 28th 2010Parking Lot Snow Stake Measurements (24 hour):
Eddies Lot: 11" new snow
Motorized Lot: 5" new snow
Sunburst Lot: 3" new snow
Johnson Pass North: 3" new snow
Friday, February 26th 20105-7" of new light density snow, limited wind, temps in teens to low 20's
- soft slabs present
Sunday, February 21st 2010In the last two weeks Turnagain Pass received 7.5 feet of snow and over 9 inches of water, with consistent rain below 1000 feet from Feb 10-19. Gale to storm force easterly winds pummeled us the last three days of the storm. The storm peaked on Feb. 18 along with the natural avalanche cycle. Many large natural avalanches occurred on all aspects and elevations.
Friday, February 19th 2010Rain line pushed to 3000 ft. 3-5 inches of water this week and 5 plus feet of snow above a fluctuating snowline.
Thursday, February 18th 201024 hour snow accumulations:
Johnson -1.5"
Sunburst - 1"
Motorized - 8"
Eddies - 8"
Monday, February 15th 201017 inches of new snow and 2 inches of water in the last 24 hours. Rain below 1000 feet and gale force easterly winds.
Saturday, February 13th 2010SNOWMACHINER FATALITY
-A snowmachiner triggered a large avalanche on the west ridge of Grandview at approximately mile 43 of the railroad tracks between Portage and Moose Pass. Two riders were caught and buried, one was killed, and one is still missing. The avalanche possibly failed on a surface hoar/crust combo.
-4 feet of new snow and 4 inches of water in the last 8 days
-Numerous medium to large natural avalanches on Friday Feb. 12 failed on buried surface hoar layers.
Friday, February 12th 2010Parking Lot Snow Stake Measurements (24 hour):
Eddies Lot: 6" new snow
Motorized Lot: 8" new snow
Sunburst Lot: 2" new snow
Johnson Pass North: trace of new snow
Wednesday, February 10th 2010Parking Lot Snow Stake Measurements (24 hour):
Eddies Lot: 3" new snow
Motorized Lot: 2.5" new snow
Sunburst Lot: .5" new snow
Johnson Pass North: trace of new snow
Tuesday, February 9th 2010Parking Lot Snow Stake Measurements (24 hour):
Eddies Lot: 3" new snow
Motorized Lot: 3" new snow
Sunburst Lot: 1" new snow
Johnson Pass North: 2" new snow
Monday, February 8th 2010Parking Lot Snow Stake Measurements taken at (24 hour):
Eddies Lot: 3" new snow
Motorized Lot: 2.5" new snow
Sunburst Lot: 1" new snow
Johnson Pass North: 1" new snow
Sunday, February 7th 2010**OUTSIDE ADVISORY AREA**
-Skier-triggered avalanche South Fork Eagle River at 3500 feet on a run locally known as "Leighow". Triggered near a shallower spot in the snowpack near a rock band, most likely recently wind loaded. It ran for 1800 feet down the chute.
Sunday, February 7th 2010Parking Lot Snow Stake Measurements (2/5 to 2/7):
Eddies Lot: 13" new snow
Motorized Lot: 10" new snow
Sunburst Lot: 8" new snow
Johnson Pass North: 6" new snow
Saturday, February 6th 2010SKIER-TRIGGERED AVALANCHE
-13 inches of new snow/1 inch water along with moderate to gale force easterly winds in the last 36 hours.
-A skier triggered an avalanche on a southwest aspect of Tincan at 3000 feet in an area called the Kitchen Wall. The skier was caught, carried, and partially buried but able to dig himself out. We estimated the slide at 150 feet wide, 200 feet long, 14 inches deep at the crown face, and 39 degrees at the trigger point. The slide failed below a recently formed windslab on a very small layer of buried surface hoar on top of a 1mm thick melt-freeeze crust.
-Numerous shooting cracks on steep rollovers breaking down about a foot deep. Recently formed windslabs (2-6 inches thick) were especially reactive, fracturing 25-60 feet wide on leeward slopes.
Tuesday, February 2nd 2010SNOWMACHINE-TRIGGERED AVALANCHE
Observed on Tuesday Feb 2. We are not sure exactly when it was triggered, but it looked recent. See photo gallery.
Friday, January 29th 2010Skier triggered avalanches on the west face of Superbowl Peak and the south side of Cornbiscuit. They measured 10 inches deep, 45-60 ft wide and ran 500 to 900 ft. Failure most likely occurred on the old snow, new snow interface where buried surface hoar is present up to 3500ft.
Wednesday, January 27th 2010Parking Lot Snow Stake Measurements:
Eddies Lot: 1" new snow
Motorized Lot: 1" new snow
Sunburst Lot: 1" new snow
Johnson Pass North: 1" new snow
Monday, January 25th 2010Sunny skies, light winds, and mountain temps in the 20's the last 5 days. Only a few isolated pockets of instability reported in addition to sluffing on 40+ degree terrain:
1/21: Small skier-triggered soft slab 1 ft. deep on Cornbiscuit
1/23: Skier-triggered soft slab on the west face of Magnum at 2500 feet. This slide was estimated at 30-50 feet wide, 1 ft. deep, and 150 feet long.
1/24: Loud whumph reported in the trees below 1500 feet north of Tincan.
Tuesday, January 19th 2010Parking Lot Snow Stake Measurements:
Eddies Lot: 2" new snow
Motorized Lot: 2" new snow
Sunburst Lot: 2" new snow
Johnson Pass North: 1" new snow
Sunday, January 17th 2010Parking Lot Snow Stake Totals (Last measurement was on Wednesday 1/13/10):
Eddies Lot: 18" new
Motorized Lot: 17" new
Sunburst: 8" new
Johnson Pass North: 6" new
Saturday, January 16th 2010Numerous soft slab avalanches running on the crust layer with whumphing at the lower elevations:
-Big soft slabs releasing on steep rollovers on Tincan.
-Ski cuts in the upper elevations of the Girdwood Valley produced 4-6 inch thick soft slabs propagating down the walls of a steep chute.
Thursday, January 14th 2010Skier Triggered avalanche on west aspect, 3800 ft, Pastoral Peak, Turnagain Pass. Steep chute with a 1.5 ft deep crown face, wall to wall, ran 900 feet, SS-AS-2-O . The bed surface was the crust layer.
Wednesday, January 13th 2010Parking Lot Snow Stake Measurements 1/13/2010
Eddies Lot:3.5 inches new snow
Motorized Lot:2.5 inches new snow
Sunburst Lot:2 inches new snow
Johnson Pass North Lot:1 inch new snow
Tuesday, January 12th 2010Parking Lot Snow Stake Measurements 1/12/2010
Eddies Lot:7 inches new snow
Motorized Lot:6 inches new snow
Sunburst Lot:5 inches new snow
Johnson Pass North Lot:3 inches new snow
Thursday, January 7th 2010Rain to 2800-3000 feet today with strong easterly winds. A few small point release wet slides observed.
Tuesday, January 5th 2010Glide Crack Avalanche Observed (see photo gallery)
We are not exactly sure when this glide crack failed, but it probably avalanched sometime on Monday Jan 4, 2010.
Monday, December 28th 2009Warm temps, strong easterly winds, and rain below 2000 feet December 21-27. Snowfall & water totals for Center Ridge Wx station 12/21-12/27: 25" snow, 3.5" SWE
Thursday, December 24th 2009MANY NATURAL AND HUMAN TRIGGERED AVALANCHE RECORDED
Most of the avalanche activity occurred on 24 hour old snow, 6-8 inches deep.
24 hours: 5-14 inches of snow fell in Girdwood, 10 inches in Turnagain Pass, and 4 inches in Summit Lake. Approximate 3 day storm totals for Girdwood 15-28 inches, Turnagain Pass 20 inches, and Summit Lake 9 inches. These amounts are above the snowline. The snowline has fluctuated from sea level to 1200 ft. Almost all precip has been rain from sea level to 800 feet.
Saturday, December 19th 2009SKIER TRIGGERED AVALANCHE
-A skier triggered a small avalanche between 2500 and 3000 feet elevation on Tincan on a slope below the main bowl. This slide was 1.5 feet deep, 20 feet wide, and ran 30 feet long.
-40 to 50 ft. long shooting cracks were reported at 3000 feet elevation on Manitoba. The wind was actively loading the slope at the time, and the cracks went down 2 feet to the new snow/old snow interface.
Thursday, December 17th 2009Snow stake totals:
Eddies Lot: 5" new
Motorized Lot: 4" new
Sunburst Lot: 3" new
Johnson Pass North Lot: 4" new
Wednesday, December 16th 2009Parking Lot Snow Measurements:
Eddies Lot: 4" new
Motorized Lot: 4" new
Sunburst Lot: 4" new
Johnson North Lot: 3" new
Tuesday, December 15th 2009Parking Lot Snow Measurements:
Eddies Lot: 3" new
Motorized Lot: 4" new
Sunburst Lot: 5"
Johnson Pass North: 4"
Sunday, December 13th 2009No new snow in the last 12 days. We had a strong inversion for 7 days from Dec 6-12 with fog down low and above freezing temps at the higher elevations. The warmest temps occurred Dec 7-9 with readings in the mid to upper 40's above 3000 feet elevation. Winds were light and variable during the inversion.
Thursday, December 3rd 2009NATURAL AVALANCHES
Medium sized Class 2 Natural Avalanches were observed on Tincan (see Photo Gallery). Large Class 3 natural avalanches observed on the south and west aspects of Sunburst and Magnum. Most of these failed on the facets on the ground during the height of the storm on Tuesday 12/1/2009.
Wednesday, December 2nd 2009Parking Lot Snow Measurements for Tuesday 12/1/09:
Tincan Lot: 24-28 inches of new wet snow
Motorized Lot: 22 inches of new snow
Sunburst Lot: 10 inches of new very wet snow
Johnson Pass Trailhead: 5 inches of new very wet snow
Sunday, November 29th 2009Parking lot storm snow totals since Monday 11/23/09
Eddies Lot: 27" new snow
Motorized Lot: 31" new snow
Sunburst Lot: 20" new snow
Johnson Pass Trailhead: 14" new snow
Saturday, November 28th 20092 feet of snow has fallen in the last 24 hours in many areas covered by this advisory. Most of that fell yesterday. 4 to 6 inches fell last night. 2 to 3 inches of water equivalent fell in this storm. Snowfall totals for the two day storm range from 1 to 2 feet at sea level and 3 to 4 feet above 500 ft.
Monday, November 23rd 2009Eddies Parking Lot: 12" new wet snow (rain/snow mix)
Motorized Parking Lot: 24" new snow
Sunburst Parking Lot: 16" new snow (rain/snow mix)
Johnson Pass Trailhead: 3" new snow

Natural avalanches and human/triggered avalanches observed in Girdwood Valley and Turnagain Pass.
Thursday, November 12th 2009Nov. 12, 2009 - 4-6 inches of new snow yesterday over the advisory area. Center Ridge station at 1000 ft in Turanagain Pass is reporting 19 inches total snowpack. Expect to see 9-10 inches at the highway elevation of 1000 ft in T. Pass. The first report of a snowboard triggered avalanche came in today. A rider lost his board yesterday at Flattop. No further details. Although outside our advisory area this reminds us that winter and avalanche season has arrived.
Tuesday, November 10th 2009Nov. 10, 2009 - 4-6 inches at 1000ft, 14-15 inches at tree line, 0-30 inches in the alpine due to wind erosion or deposition.
Monday, October 12th 2009Oct. 12, 2009 - Very warm start to October. Snow line back to 4000 ft. Most ridgetop snow has melted back in the advisory area. Valley temps in the 50's. An ENSO (El Nino Southern Oscillation ) pattern is forecasted for the 09-10 season. This is subject to debate but usually means warmer, drier temps for us in general. Although remember 1998-99 (~1000in).
Thursday, September 24th 2009Sept. 24, 2009 - First measurable snowfall at higher elevations. Snow continued through Oct. 25. Approx. 3-4 inches with up to a foot in the Upper Glacier Creek drainages. Snow line approx. 2000 ft.

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):

Mar 12th, 2010 -- Mar 14th, 2010
  Level 1 Backcountry Avalanche Hazard Evaluation and Rescue Course
Great intro to safe backcountry travel! Given by AK Avalanche School. Location: Turnagain Arm. 3 Full Days. Visit AlaskaAvalanche.com for details
Mar 17th, 2010
6:30 PM
  Decison Making in the Backcountry
The CNFAIC will talk at the Mountaineering Club of AK meeting on March 17th at the BP Energy Center. The meeting is open to the public and starts at 630 pm. Carl Skustad will present a talk on Decision Making in the Backcountry using Web based technology. Learn how avalanche forecasts are made and how you can make your own.
Mar 19th, 2010 -- Mar 22nd, 2010
  Level 2 Backcountry Avalanche Hazard Evaluation Course
Hone your avy knowledge! Given by AK Avalanche School. Location: Hatcher Pass & Turnagain Arm for 4 Full Days. Visit AlaskaAvalanche.com for details
Mar 23rd, 2010 -- Mar 28th, 2010
  7th Annual Jeff Nissman TelePalooza Festival
It's all happening at Alyeska Resort in Girdwood. Visit: telepalooza.com
Apr 2nd, 2010 -- Apr 4th, 2010
  Women’s Backcountry Travel Weekend - Valdez
Become an Avy Savvy gal! Women’s Backcountry Travel Weekend at Thompson Pass. Build competence and confidence to make good decisions in avalanche terrain. This introductory class focuses on planning and preparation, terrain selection and human factors. Avalanche rescue skills will be covered as well. All women – all fun. The instructor is Sarah Carter. visit www.alaskasnow.org for more info
Apr 9th, 2010 -- Apr 10th, 2010
  Alaska Avalanche School - Wet Snow Evaluation Workshop
Wet Snow Evaluation Workshop Location: APU & Turnagain Arm for 1.5 Days $135 visit alaskaavalanche.com for more info