Chugach State Park

Fri, December 8th, 2023 - 7:00AM
Sat, December 9th, 2023 - 7:00AM
Mary Gianotti
Conditions Summary

Weekend Avalanche Outlook

Saturday, Dec. 9th to Sunday, Dec. 10th

Bottom Line: Our biggest concern going into this weekend is triggering a large avalanche breaking on weak snow at the base or the middle of the snowpack. These layers are more reactive at higher elevations (above around 2,500-3,000 feet).  We are also concerned about a person triggering a  wind slab avalanche 1-3’ deep. We are anticipating dangerous avalanche conditions this weekend, so steep terrain should be approached with caution.

Special Announcements

Welcome to the Chugach State Park conditions page. We are in the process of ramping up a weekend avalanche report for Anchorage’s Front Range. Our goal is to provide avalanche information for high use areas of the Chugach State Park in an effort to assist recreationalists in making informed and safe backcountry travel decisions.

Areas include the Anchorage Front Range (i.e., Flattop/Glen Alps) and the South Fork of Eagle River. The outlook’s primary audience will be winter hikers, backcountry skiers/snowboarders, snowmachiners, snowshoers, fat bikers, and climbers.

Recent Avalanches

Recent Avalanches:  A skier triggered a small wind slab avalanche on Peak 3 this afternoon (details here). Nobody was caught or carried in the avalanche. We are also consistently finding concerning results in snow tests on two weak layers – one in the middle and one at the base of the snowpack.

Weather Recap: In the past week the Front Range had quite a bit of wind at higher elevations with two northwest outflow events and multiple periods with strong easterly winds. Between December 1st and December 7th, we received just 1 inch of snow in the Front Range. However, in the last 24 hours, the Glen Alps weather station recorded 12 inches of new snow, and Indian Pass received 8 inches.

Looking at the weather forecast for this weekend, it’s expected to be mostly cloudy with some light to moderate winds from the NE. The temperatures will be between just below 0 to the mid teens F, and we might get a trace to 4 inches of snow.

With low early-season snowfall prior to the early November superstorm  and  multiple periods of strong winds since it started snowing, total snow depth is variable across this forecast zone. Some terrain has almost no snow, especially on SE slopes, while on other slopes the winds have deposited over 8 feet of snow.

Avalanche Problem 1
  • Persistent Slabs
    Persistent Slabs
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
More info at

There are two weak layers we have found in the snowpack at the higher elevation alpine start zones. One is a thin layer of facets right above the Thanksgiving crust and the other is a layer of larger facets at the base of the snowpack. We don’t know of any avalanches that have released in these layers yet, but over the last week, we consistently found unstable test results on both of these layers (see our observations from the South Fork of Eagle River and Peak 3 for details). These layers are concerning and something we are watching closely, especially with the new snow and winds from last night adding stress to the snowpack. We’ve found both layers in the South Fork of Eagle River, Arctic Valley, and Peak 3, and they are most pronounced at elevations over ~2,700ft. Some common red flags for an unstable snowpack are the “whumphing” sound of the snowpack collapsing beneath you or cracks in the snow that shoot out from you. Any of these signs are clearly telling you the slope can avalanche if it’s steep enough. That being said, the absence of these red flags does not necessarily mean the slope is safe.  Steep terrain needs to be approached with caution this weekend, and will require a thorough snowpack assessment to travel safely.

With low snow totals in the Front Range and ample snow at Turnagain Pass, skier traffic has been slow in Chugach State Park. Part of the reason we have seen such limited avalanche activity in the Front Range is simply because there haven’t been a lot of people getting out in this area. Now, with the new, less dense snow from last night covering the layers we’re worried about in the Front Range, we think there’s a higher chance of a person causing an avalanche this weekend.

Snowpit at Eagle River showing unstable test results on the weak layer at the base of the snowpack 12.5.2023

Snowpit dug at Peak 3 showing signs of instability on thin facet layer above the Thanksgiving crust 12.7.2023

Avalanche Problem 2
  • Wind Slabs
    Wind Slabs
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
More info at

This week, we saw several periods of strong winds at higher elevations, forming across the entire Chugach State Park. These are mostly on north- and west- facing slopes. These slabs can be anywhere from one to three feet deep or even more. A wind slab on the surface will feel firmer than snow that has been sheltered from the winds Wind Slabs can be avoided by sticking to sheltered or wind-scoured areas. Keep in mind, given the poor snowpack structure described in Problem 1 above, a relatively small wind slab triggered near the surface has the potential to step down to a deeper weak layer, making a bigger avalanche.

Winds ripping across the Front Range on 12.6.23. Photo by Wendy Wagner

Wind affected snow at the South Fork of Eagle River 12.5.23


Fri, December 8th, 2023

Weather Forecasts:

Weather Stations

Recent Observations for Chugach State Park
Date Region Location
05/29/24 Chugach State Park Avalanche: Harp mtn west aspect
05/07/24 Chugach State Park Observation: Mt. Eklutna
04/27/24 Chugach State Park Avalanche: Chugach Front Range Powerline Valley
04/16/24 Chugach State Park Observation: South Fork of Eagle River
04/13/24 Chugach State Park Avalanche: South Fork Hiland Road
04/10/24 Chugach State Park Observation: Chugach Front Range Flattop
04/09/24 Chugach State Park Observation: South Fork of Eagle River
04/08/24 Chugach State Park Avalanche: Arctic Valley/ Gordon Lyon
04/06/24 Chugach State Park Observation: Eagle River South Fork
04/06/24 Chugach State Park Avalanche: False Peak

This is a general backcountry conditions summary. This advisory does not apply to highways, railroads or operating ski areas.