Chugach National Forest and
Alaska State Parks Reports

Chugach National Forest

February 16, 2008
Good morning backcountry travelers this is Carl Skustad with the Chugach National Forest Avalanche Information Center on Saturday, February 16th at 630 am.

Weather Observations
In past 24 hours:
The Center Ridge weather station at 1800 feet in Turnagain Pass recorded 0 inches new snow. Total snowpack depth is 93 inches (1 inch less than yesterday). This weeks snow totals are 16 inches in Turnagain Pass and 23 inches at Alyeska. The temperature this morning is 17 deg F at Center Ridge.

Sunburst weather station at 3800 feet in Turnagain Pass recorded gale force winds mid week. Strong NE winds loaded leeward slopes this week. Winds subsided yesterday but are quickly increasing this morning with gust already in the 50’s. Ridge top temps are 8-11 deg F.

Snow has started falling again this morning. The radar and satellite images show heavy snowfall heading our way. Temps are forecasted to rise and snow will switch to rain this afternoon in coastal areas. Very strong NE winds are also associated with this storm front.

Bottom Line (Primary Avalanche Concerns)
The avalanche hazard will increase today as new snow and wind enters the area. Today natural and human triggered avalanches will be likely on steep alpine slopes in areas that receive heavy wind or new snow.

1. New snow loading wind slabs

2. The most recent layer of buried surface hoar that formed over the past two weeks. This weak layer is buried about 16-23 inches deep. This layer is fairly widespread in the Kenai and Chugach Mountains.

Avalanche and Snowpack Discussion (More detailed info…)
Yesterday an avalanche in the Seattle Creek drainage killed two snowmachiners. The large avalanche was triggered by the riders on a steep, leeward, loaded aspect under a cornice. Two other riders were dug out successfully by the remaining two members of the group. All riders where wearing beacons and had rescue gear. Without the quick rescue of the two surviving victims we would likely have had four fatalities. I will be riding to the site to do an assessment today.

Another very large human-triggered avalanche was reported on Magnum. Nobody was caught or injured in this avalanche. It was triggered remotely while a skier was digging a snow evaluation pit at the top of the West face above the highway. Preliminary reports called it a large class 3 small class 4 that propagated about 3000 feet across the slope. It was reported as 1 meter deep. Sounds like it failed on an "odd melt-freeze layer" that was older and deeper than the most recent layer of buried surface hoar. We will follow up and get more information on this avalanche as well.

As mentioned over the last three days, this layer of buried weak snow is no joke. It’s the type of weak layer that catches an overwhelming number of backcountry travelers and is responsible for many fatalities. Additional snowfall and strong NE winds are forecasted for the Turnagain Arm area today. If this is the case, or snowpack will be loaded to a point that natural avalanche activity could occur. We have not seen the height of this avalanche cycle in the Turnagain Arm area. We had wide spread collapsing in the snowpack we were skiing yesterday on Tincan Mountain. I also heard of a partial snowmachiner burial in the Skookum (Placer) drainage yesterday. This snow pack instability extends from Girdwood south to Seward and the Kenai Mountains. Although we have no data or observations from the Chugach State Park, they have also received significant snowfall and wind. I expect there to be an increased avalanche hazard in many areas of the Park as well. There is lots of great quality snow on lower angle terrain that can be enjoyed this weekend.

Travel on slopes steeper than 30 degrees is not advised. The mountains are all about timing and right now is not the time to travel on or under steep slopes.

Alaska State Parks