Hatcher Pass Avalanche Forecast
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The Bottom Line
The most recent storm brought 2″ of water and between 18-20” of new snow to the forecast area. This new snow has caused stress on a crust in the middle of the snow pack and on the weak snow near the ground.
Human-triggered persistent slab avalanches 2-4’ deep are possible at all elevations and all aspects on slopes 30º or steeper.
Human-triggered dry loose avalanches are possible in terrain 40º and steeper.
Natural avalanches are unlikely.
An avalanche of any size can have severe consequences near rocks, cliffs, gullies and other hazards.
The current height of snow at the Marmot Snow Stake at 3000’ is just shy of 3 feet. We just doubled our snowpack.
NWS forecasts are calling for strong winds from the north today. If this lasts for more than a few hours avalanche danger will increase rapidly. Pay attention to any signs of active wind loading at upper elevations and near ridge lines.
No new slab avalanches have been observed since Nov 16th. Visibility was extremely limited over the last few days, Natural avalanches may have occurred and not been reported or observed.
| 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 |
Starting on 12/5 18-20” of new snow has fallen with 2” of SWE. Human-triggered persistent slab avalanches 2-4’ deep will be possible at all aspects and elevations on slopes 30º or steeper. Natural avalanches are unlikely. If an avalanche does occur it will likely fail on a recent rain crust (12/5) in the mid-pack and step down or fail at the ground. It has been 24 hours since the last snowfall and stability is expected to be slowly improving.
The rain crust failed on isolation in this stability test. The rain crust is buried about 1 foot deep.
Collapsing and shooting cracks will be red flags for this avalanche problem. Additional ways to identify this avalanche problem are to use hand pits, pole probes, and other traveling tests. Feel for a crust about one foot below the surface and look for weak sugary faceted snow on the ground. Formal Stability tests will also help you identify this avalanche problem.
The current snowpack has a flawed structure and tests have been failing on isolation. Be thoughtful about the slopes you travel on if you decide to head into avalanche terrain. Start on small low consequence terrain features before exploring large steep slopes. Have a plan and use terrain progression to stack the odds in your favor.
An avalanche of any size will likely have severe consequences due to the fact it will fail near the ground, increasing the chance of traumatic injury.
Continue to use safe travel protocol in avalanche terrain:
| 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 |
With 18-20” of new snow human-triggered dry loose avalanches will be possible on slopes 40º or steeper. If you do choose to venture into steeper terrain use good sluff management, to avoid being swept over cliffs and other hazards.
