Hatcher Pass Avalanche Center

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ARCHIVED - Forecasts expire after 24 hours.
Issued
Sat, February 3rd, 2024 - 7:00AM
Expires
Sun, February 4th, 2024 - 7:00AM
Forecaster
Allie Barker
Avalanche risk The Bottom Line

The avalanche danger is MODERATE for dry loose avalanches (sluffs) at all elevations where triggering a sluff large enough to injure or bury a person is possible. Natural avalanches are unlikely.

Today will mark the 7th day in a row with below zero temperatures, more faceted powder than the day before, and a great day to get after big objectives with few avalanche concerns.

Sustained cold temperatures will taper Sunday as the next low pressure system arrives bringing 3 to 5 inches of new snow to the forecast area.

 

Special Announcements

The HPAC Cabin Fever Reliever with The Jangle Bees and the drawing for our winter raffle are coming up next weekend, 2/10! Get your tickets to the party and raffle tickets today! All proceeds support HPAC and sustainable avalanche forecasting in Hatcher Pass.

 

Sat, February 3rd, 2024
Upper Elevation
Above 3,500'
2 - Moderate
Avalanche risk
Mid Elevation
2,500'-3,500'
2 - Moderate
Avalanche risk
Low Elevation
Below 2,500'
2 - Moderate
Avalanche risk
Sun, February 4th, 2024
Upper Elevation
Above 3,500'
2 - Moderate
Avalanche risk
Mid Elevation
2,500'-3,500'
2 - Moderate
Avalanche risk
Low Elevation
Below 2,500'
2 - Moderate
Avalanche risk
Sun, February 4th, 2024
Upper Elevation
Above 3,500'
2 - Moderate
Avalanche risk
Mid Elevation
2,500'-3,500'
2 - Moderate
Avalanche risk
Low Elevation
Below 2,500'
2 - Moderate
Avalanche risk
0 - No Rating
1 - Low
2 - Moderate
3 - Considerable
4 - High
5 - Extreme
Avalanche risk Avalanche risk Avalanche risk Avalanche risk Avalanche risk
Travel Advice Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential. Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
Likelihood of Avalanches Natural and human-triggered avalanches unlikely. Natural avalanches unlikely; human-triggered avalanches possible. Natural avalanches possible; human-triggered avalanches likely. Natural avalanches likely; human-triggered avalanches very likely. Natural and human-triggered avalanches certain.
Avalanche Size and Distribution Small avalanches in isolated areas or extreme terrain. Small avalanches in specific areas; or large avalanches in isolated areas. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. Large avalanches in many areas; or very large avalanches in specific areas. Very large avalanches in many areas.
Recent Avalanches

Few people have been out recreating this week most likely due to the extreme cold temperatures. Folks that have been braving the cold have been triggering mostly small to medium size dry loose avalanches (sluffs) in steep terrain 40º and steeper on all aspects above 3000 ft. A couple small shallow slab avalanches have been observed or reported this week in isolated locations and extreme terrain. These slabs have either triggered sluffs or sluffs have triggered small slabs a couple inches thick.

2/2 Human triggered avalanches on Skyscraper SSE 4000′

 

2/2 Natural dry loose avalanche , Martin Mine SSE 4000′

 

2/2 Natural dry loose avalanches in the Lodge Run off Marmot WSW 4000′

 

2/2 Natural dry loose avalanches , Eldorado Bowl SE 4400′

 

2/2 Natural dry loose avalanches on Idaho Peak SSE 3900′

 

2/2 The wolverine strikes again? Sluff triggered small slab on lower marmot S 3100′

Avalanche Problem 1
  • Dry Loose
    Dry Loose
  • Aspect/Elevation
  • Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
Dry Loose
Dry Loose avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

Aspect/Elevation of the Avalanche Problem
Specialists develop a graphic representation of the potential distribution of a particular avalanche problem across the topography. This aspect/elevation rose is used to indicate where the particular avalanche problem is thought to exist on all elevation aspects. Areas where the avalanche problem is thought to exist are colored grey, and it is less likely to be encountered in areas colored white.

Likelihood of Avalanches
Terms such as "unlikely", "likely", and "certain" are used to define the scale, with the chance of triggering or observing avalanches increasing as we move up the scale. For our purposes, "Unlikely" means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. "Certain" means that humans will be able to trigger avalanches on many slopes, and natural avalanches are expected.

Size of Avalanches
Avalanche size is defined by the largest potential avalanche, or expected range of sizes related to the problem in question. Assigned size is a qualitative estimate based on the destructive classification system and requires specialists to estimate the harm avalanches may cause to hypothetical objects located in the avalanche track (AAA 2016, CAA 2014). Under this schema, "Small" avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become "Large" enough to bury, injure, or kill people. "Very Large" avalanches may bury or destroy vehicles or houses, and "Historic" avalanches are massive events capable of altering the landscape.

Signal Word Size (D scale) Simple Descriptor
Small 1 Unlikely to bury a person
Large 2 Can bury a person
Very Large 3 Can destroy a house
Historic 4 & 5 Can destroy part or all of a village
More info at Avalanche.org

After an insanely bitter cold week of weather with temperatures that even the old timers might whine about we have one predictable avalanche problem to contend with. The last recent storm on 1/28-29 deposited 5 to 8 inches of new low density snow followed by moderate to strong wind. The short duration of wind transported the low density snow surprisingly fast, creating variable conditions early in the week. However, over the several days cold temperatures have assisted wind slabs in deteriorating and faceting out, losing density and contributing to a dry loose avalanche problem this week.

The most likely locations for triggering a dry loose avalanche (aka sluff) today will be on steep convexities and rollovers in terrain 40º and steeper on all aspects and all elevations.  They are most hazardous if you are caught and carried into a terrain trap such as a gully, cliff, or couloir.  While most sluffs will be small, getting caught in steep terrain that funnels into any terrain trap has the potential to increase the size, risk and consequence of an avalanche.

On southerly aspects where dry unconsolidated snow sits on firm bed surfaces, sluffs will be more likely to trigger and result in a larger volume of debris. It will be possible to get caught and carried, injured, or tweek a knee in this terrain. As a result of the prolonged cold temperatures this week, sluffs are moving slowly and so are we. Sluff management and mitigating a sluff may be challenging today due to the slow nature of the snow and inability to get enough speed to ski or ride fast enough to avoid or outrun debris.

In isolated and extreme locations it will be possible to either trigger a sluff that propagates a small shallow slab avalanche or vice versa. Most likely locations are upper elevation, near ridgelines in areas previously exposed to the wind.

2/2 Natural and human triggered dry loose avalanches (sluffs) on Marmot from 2/1-2 SSW 4400′

 

Weather
Sat, February 3rd, 2024

NWS AVG Forecast here.

NWS point forecast here.

Marmot Weather Station here.

Independence Mine Snotel here.

Frostbite Bottom Snotel here.

State Parks Snow Report and Motorized Access information here.

XC trail grooming report for Mat-Su, Anchorage, and Kenai here.

Observations
Recent Observations for Hatcher Pass