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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sat, January 30th, 2021 - 7:00AM
Expires
Sun, January 31st, 2021 - 7:00AM
Forecaster
HPAC Staff
The Bottom Line

Small, slow moving, and low volume, dry loose avalanches will be possible to trigger at all elevations, on all aspects, and only on slopes 40° and steeper.

Thin coverage, the recent new coat of white paint on the mountains is all show! Coverage is lacking, rocks linger just below the surface. The upper elevation steeps need more snow, and the mid elevation band has slightly better coverage. Conditions appear very tempting, but going fast almost ensures either gear damage or worse.

 

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Sat, January 30th, 2021
Upper Elevation
Above 3,500'
Low (1)
Avalanche risk
Mid Elevation
2,500'-3,500'
Low (1)
Avalanche risk
Low Elevation
Below 2,500'
Low (1)
Avalanche risk
Upper Elevation
Above 3,500'
Avalanche risk
Low (1)
Mid Elevation
2,500'-3,500'
Avalanche risk
Low (1)
Low Elevation
Below 2,500'
Avalanche risk
Low (1)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Avalanche Problem 1
  • Dry Loose
    Dry Loose
  • Almost Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic
    Very Large
    Large
    Small
    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.

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

It will be possible to human trigger small loose dry avalanches on all aspects at all elevations on slopes 40º and steeper.

“Sluffs” will generally be slow in speed, low in volume, and manageable. 2-4″ of newer, low density snow on the surface will fail on older, near surface facets below. The volume may be larger where older snow is entrained. Any dry loose will be easy to ride through, making capture or carry unlikely.

At ridgelines in the upper elevations, recent light to moderate gusts have formed extremely small, and barely cohesive slabs, 4-6″ thick, on leeward aspects, Southwest to North. These are possible to human trigger, initially fail like mini-slabs, however, the density of the snow is so low that they quickly transition to loose dry avalanches. These are failing on the same weak layer of older near surface facets.

Natural dry loose avalanches are unlikely, but if they do occur it will be in isolated locations, on south to west aspects, where direct solar radiation heats up exposed dark rocks affecting the surrounding snow. Today the temps are cooler and the sun will be struggling to heat anything up.

Eldorado Headwall, East aspect, 4300′. Recent natural dry loose, shallow, low to moderate volume.

Another reminder on thin coverage. The new thin blanket of snow is a nice coat of paint, but it’s all show. Be cautious as thin coverage and rocks are plentiful and dangerous. Keep your travel speeds slow. A few snow machines have recently been damaged due to riding in thin coverage, and it’s common to bottom out and hit rocks.

 

 

Weather
Sat, January 30th, 2021

New snow totals:

1/26: Independence Mine, 1″

1/28: Independence Mine, about 2″

Cold, clear and light variable winds have been the trend this week. On Sunday 1/24 temperatures were in the mid 20s and began to drop into the teens. While temps began to drop the sky began to clear and light variable winds with moderate gusts began. These conditions have persisted this whole week.  The surface snow remains mostly unaffected by the winds. Along with the uneventful winds, cold temperatures have assisted in keeping the new snow from becoming cohesive. Most areas have low density powder sitting over older, weak, near surface facets.

This morning the temperature at the Palmer airport is 13F, at 3500′ it’s 17F, and at 4500′ it’s 19F, with clam winds and clear skies. The forecast for today is for uneventful weather, with temps at 1000′ 18F, and slightly warmer at 3000′ 22F, with winds light from variable directions. No precipitation expected. Temperatures should drop tonight into the single digits down low, with temps in the teens up high.

Colder temps are in store for the next several days. This morning Willow hit -7F.


Marmot last 24hrs


NWS Rec Forecast here.

NWS point forecast here.

State Parks Snow Report and Motorized Access information here.

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