Hatcher Pass Avalanche Center

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ARCHIVED - Forecasts expire after 24 hours.
Sat, April 8th, 2023 - 7:00AM
Sun, April 9th, 2023 - 7:00AM
Tim Rogers
Avalanche risk The Bottom Line

The avalanche hazard is MODERATE for DRY LOOSE on steep, upper elevation NORTH facing slopes.

Normal Caution is advised for small pockets of instabilities along northerly facing ridgelines where lingering areas of wind loaded and faceted snow still exist. Additionally, if the sun comes out for any sustained period this weekend, new snow will be easily effected on steep south facing slopes.

Thursday night’s clear, cold conditions were enough to dry out the recent sun effected snow we received and helped make for excellent riding conditions. This weekend is calling for new snow, and although accumulations look modest and winds user friendly, conditions will be changing over the next few days.

Special Announcements

A sincere thanks to everyone at HPAC for the opportunity to come up here and help out for a few weeks. Quite a spot y’all have got, I hope to see you again next year!

Sat, April 8th, 2023
Upper Elevation
Above 3,500'
2 - Moderate
Avalanche risk
Mid Elevation
1 - Low
Avalanche risk
Low Elevation
Below 2,500'
1 - Low
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

Yesterday forecasters observed numerous natural and human triggered dry loose slides on steep, northerly facing slopes. While these slides were all relatively small and manageable, many of them had entrained enough snow on the way down the slope that you would not want to be caught in them.

Tracks and sluffs on Government Peak. NE facing 4500 ft.

A party earlier this week reported triggering a small but energetic slide on a wind-loaded NE facing slope off of 4068. Forecasters observed some similar natural activity below Hatch peak. While the winds have been light and temperatures mild, these slides are a reminder that small, localized instabilities remain on upper elevation terrain.

Earlier this week, warm temperatures, high humidity, and periods of sun encouraged both natural and human triggered wet loose activity.

Roller balls and some wet sluffing on Marmot. W/NW Facing 3600 ft.

Recent Conditions

Between Tuesday and Thursday Hatcher Pass picked up about 5-7’’ of light density snow, mostly at upper elevations. This snow was affected by periods of warm temperature, high humidity, and some direct sunlight, causing it to settle out, initiate some wet loose activity, and form a crust on steep solar aspects.

Thursday night’s cold, clear conditions helped radiate out some of the moisture in the snow surface and many parties were finding soft dry turns on all aspects on Friday. Even though the sun was out, a light breeze and relatively cool temperatures helped keep the snow surface from getting too wet. That said, steep solar slopes were being warmed and may have a thin crust on them going into this next period of snow.

Easy to get new snow moving on steep northerly slopes. 4500 ft North facing.

As they say, today’s snow surface is tomorrow’s weak layer.  The most important part of this forecast is likely understanding what kind of surface this weekend’s snow will be falling on. Our recent low density and recrystalized snow surface will likely prove to be an easy weak layer for more dry loose or storm slab activity to fail on as new snow starts to accumulate.

Avalanche Problem 1
  • Dry Loose
    Dry Loose
  • Certain
    Very Likely
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
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.

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

The biggest hazard going into the weekend will continue to be the potential for triggering small dry loose avalanches in steep terrain, mostly on the north half of the compass. These slides will likely be 4-6’’ deep and could run several hundred feet where slopes have a sustained angle above 40°.

Recent snow was relatively light density, good on some moisture, and has since dried out and recrystalized  after Thursday’s cold, clear night. We observed numerous sluffs point releasing from steep rocks, cornices, and from skier traffic. While these slides had no propensity for propagation, many of them are were running to where the slope transitioned and entraining all the new snow as they went.

Be aware that the surfaces these sluffs are running on may change their speed and behavior and make them a little more difficult to deal with. When you’re on the slope, allow sluffs to run in front of you or move to the side to get out of the way. Remember that as new snow accumulates this weekend, these slides will likely become more deep and energetic.

Sat, April 8th, 2023

Independence Mine Snotel reported picking up 5-7’’ of snow at about 1/2’’ of snow water equivalent between Tuesday and Thursday. On Tuesday and Wednesday, this snow was affected by periods of warm temperatures, high humidity, and strong sun causing it to settle out considerably. Clear, cold conditions on Thursday night dried it back out a bit again and there’s now loose, cold snow on most aspects.

Although winds have remained light, small, localized wind effects can be found on upper elevation ridgelines.

It’s currently snowing up at Hatcher Pas and this weekend looks like a return to active weather with a couple of inverted troughs bringing precip in from the east/southeast. Accumulations look modest with an inch or so expected Saturday and 2-4’’ possible mostly early am Sunday. Winds look to remain light but will shift to the North by the end of the weekend.

Day 1 QPF snow for HP

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.

Recent Observations for Hatcher Pass