Hatcher Pass Avalanche Center
Hatcher Pass

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ARCHIVED - Forecasts expire after 24 hours.
Issued
Sat, March 26th, 2022 - 7:00AM
Expires
Sun, March 27th, 2022 - 7:00AM
Forecaster
Allie Barker
Avalanche risk The Bottom Line

Small to large wind slabs and persistent slabs will be possible to human trigger today at upper elevation on West to North aspects.

Small loose wet sluffs will be possible on southerlies in the afternoon below 2500′.

The danger is low at all other elevations and aspects.

Natural avalanches are unlikely today.

Evidence from the wind ravaging Hatcher Pass will be hard to miss this weekend. However, a few protected locations still harness powder. Crusts are burly and are not softening up during the day above 3000′.

Enjoy the sunshine, conditions will improve!

Special Announcements

The Hatcher Pass Snow Riders are continuing to groom trails. Thank you!

The road is still closed at mile 14/Goldmint and likely will be for awhile because of resources needed for the large avalanche in Eagle River and elsewhere.

Sat, March 26th, 2022
Upper Elevation
Above 3,500'
2 - Moderate
Avalanche risk
Mid Elevation
2,500'-3,500'
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

No new avalanches have been observed or reported since Thursday.

Below are a few pictures of avalanches earlier in the week.

To see more avalanches from earlier in the week, click obs here and Thursday forecast here.

3/25 Glide crack opening up in the Nosehairs

 

3/25 Wet loose from earlier in the week between the Nosehairs and Pinnacle valley

 

3/25 Wet loose off Marmot from earlier in the week

Avalanche Problem 1
  • Wind Slabs
    Wind Slabs
  • Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
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.
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

2-6″ thick wind slabs will be possible to human trigger in specific locations at upper elevation, especially near ridgelines and cross loaded features, on West to North aspects, on slopes steeper than 35º. Natural avalanches are unlikely.

Winds gusted E 24-38 mph for 16 hours over the past several days and began to taper Friday afternoon. Evidence of wind slabs and sastrugi is most obvious on the Arkose Ridgeline, south of the Little Su where winds were stronger this week compared to IM bowl. The thickness of the slab will vary considerably depending on where you travel this weekend.

It will be possible for wind slabs to step down into the persistent slab, increasing the size and consequence of an avalanche.

To identify this avalanche problem use pole/probes and stability tests. Look for smooth, wind drifted snow. Listen for hollow, drum-like sounds. Cracking and whumping are red flags for this avalanche problem.

 

East winds gusted in the 30’s for over several days this week

 

Wind textured snow. Near gold chord lake, exiting Nosebleed, Microdot.

 

Many snow surfaces have been ravaged by the wind.

Avalanche Problem 2
  • Persistent Slabs
    Persistent Slabs
  • Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
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.
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

8-16″ thick Persistent slabs will be possible to human trigger in isolated locations on West to North aspects at upper elevation on slopes steeper than 30º. Natural avalanches are unlikely.

Finding a slab sitting on top of buried surface hoar or buried near surface facets (weak sugary snow) is getting more challenging but still exists in isolated locations.

 

To identify this avalanche problem use hand pits, pole/probes and formal stability tests. The weak layers are shallowly buried, up to 16″ deep, so digging a pit will give you good information about these weak layers and whether they exist in your location.

Whumping and shooting cracks are red flags for this avalanche problem.

 

Avalanche Problem 3
  • Wet Loose
    Wet Loose
  • Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
Wet Loose
Wet Loose avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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

Small, loose wet sluffs will be possible in the afternoon on steep southerly aspects below 2500′ on slopes steeper than 35º.

Temperatures at Frostbite station (2700′) have remained above freezing on 3/24 and barely froze on 3/25. Cooler temps and firm crusts will persist above 3000′ today.

Pay attention to this as it is an indicator of larger wet avalanche problems to come this spring.

  • Manage loose avalanches by staying out of constricting terrain, like drainage gullies, and moving out of the fall line so you don’t get caught by your own sluff.
  • Avoid being caught and pulled into terrain traps below you like trees, gullies, or benches.
  • Roller balls, pinwheels, and natural sluffs of wet surface snow indicate potential for more wet activity.
  • Natural loose wet avalanches could start in rock bands or cliffy areas and fan out, entraining moist surface snow on steep slopes below.
Weather
Sat, March 26th, 2022

NWS AVG Forecast here.

NWS Rec Forecast here.

NWS point forecast here.

State Parks Snow Report and Motorized Access information here.

Observations
Recent Observations for Hatcher Pass