Avalanche Forecast | Hatcher Pass Avalanche CenterAvalanche Forecast | Hatcher Pass Avalanche Center 02/09/2023

Thu, February 9th, 2023

Upper Elevation

Above 3,500'

2 - Moderate

Mid Elevation

2,500'-3,500'

2 - Moderate

Low Elevation

Below 2,500'

2 - Moderate

0 - No Rating

1 - Low

2 - Moderate

3 - Considerable

4 - High

5 - Extreme


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

On Feb 6th small human-triggered wind slabs were reported on Microdot. These wind slabs have likely gained strength and bonded with the underlying snow.

Avalanche Problem 1

Dry Loose
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.

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

Currently, there is 8-10 inches of low-density snow at the surface of the snowpack. This low-density snow was formed by several small storms over the last 8 days and will be capable of producing dry loose avalanches.

Human-triggered dry loose avalanches are possible. These avalanches will be small to large in size and found on slopes 40 degrees and steeper. Natural avalanches are unlikely.

Layers that were formed by the wind on Feb 5- 6th have likely bonded well with the snow underneath, in some isolated areas this layer may still be reactive. This layer may act as a bed surface for dry loose avalanches.

The snowpack has a variety of crusts and old wind slabs underneath 8-10 inches of low-density snow. These layers are currently not a problem and will need a major loading event to reactivate them. See photo below for a better idea of the snowpack structure.

The old Christmas wind slab is sitting on top rounding facets, this layer showed some failure but did not propagate during our tests.

Any size dry loose avalanche can have severe consequences if you are swept off your feet and carried through cliffs, rocks, and other hazards. If you do decide to travel in steep terrain good sluff management will be important. Dry loose avalanches will be able to entrain surrounding snow and travel quickly.

NWS is calling for temperatures in the single digits allowing for the snow surfaces to facet and gain no cohesion.

The riding quality has improved with all the small storms over the week. Today should be a fun but cold day to be in the mountains.

Weather

Thu, February 9th, 2023

Snow totals from 2/1-2/9

2/1: 2 inches of new snow

2/3: 4 inches of new snow at independence mine

2/5: 2-3 inches of new snow, 0.2″ of SWE

2/6: 4 inches of new snow, 0.4″ of SWE

2/7-8: 2 inches of new snow, 0.2″ of SWE

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