Hatcher Pass
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The Bottom Line
The avalanche danger is CONSIDERABLE today at all elevations where intense snowfall has rapidly accumulated over the past 5 hours and will continue to contribute to wind and storm slabs and dry loose problems throughout the day.
Expect strong winds from Saturday to have built sensitive slabs that will be lurking under the new snow and potentially hard to identify on west to northeast aspects at upper elevation.
Hatcher Pass will continue to see a RAPID load throughout the day with up to 12 to 16 additional inches of new snow over 24 hours combined with strong winds.
Careful snowpack evaluation, cautious route-finding and conservative decision making is essential.
New snow rapidly accumulating at the Marmot lodge snowstake this morning.
Special AnnouncementsToday’s forecast is a bonus forecast due to the considerable avalanche hazard. If you value additional info from HPAC please consider donating today.
Hatch Peak weather station is online!
| Mon, December 18th, 2023 |
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| 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. |
One human triggered slab avalanche was reported on Saturday on Hatch Peak. See info here
Other reports of natural dry loose and storm slabs were reported but not verified due to poor low light conditions.
| 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 |
Another sneaker stormstorm is rapidly impacting Hatcher Pass this morning and will continue throughout the day.
Snowfall totals as of 5am this morning:
8″ new snow with 0.7″ SWE at IM/3550′
7″ new snow with 0.6″ SWE at Frostbite/2700′
Marmot winds ESE G34-46mph 9 hrs on Saturday
Wind slab avalanches:
Strong to extreme winds at 4500′ gusted ESE 34 to 46mph for 8 hours on Saturday have contributed to and will continue to build slabs throughout the day with additional new low density snow. Expect slabs 6 to 12″ thick to be found mostly at upper elevation on west to northeast aspects (clockwise) on slopes steeper than 35º. Yesterdays wind slabs may be sitting on buried weak sugary snow (near surface facets) which has the potential to increase the size of the avalanche.
At 6 am this morning, strong southerly winds have been reported at the Marmot (4500′) and Hatch (4561′) weather stations with gusts reaching 34 to 44mph. Expect wind slabs to increase in size and sensitivity throughout the day.
Pay close attention to wind transported snow and avoid steep wind drifted terrain in all elevations. Shooting cracks and sometimes audible collapses are indicators of instability. Look for hard snow sitting over weaker snow, smooth and rounded or lens shaped features.
Storm slab avalanches:
Storm slabs will be building throughout the day on all aspects, at all elevations, on slopes steeper than 35º. To identify this avalanche problem use formal stability tests and hand pits to see if the new snow is behaving like a slab. Shooting cracks and whumping will be a red flag for this avalanche problem.
Dry loose avalanches:
8″ of low density snow this morning combined with an additional 12″ forecasted today will make triggering a sluff likely on steep slopes greater than 40º on all aspects, at all elevations. Rapidly growing cornice chunks or a wind slab could entrain a good degree of loose snow, making a small avalanche quite large. Rapid snowfall throughout the day will continue to contribute to this problem throughout the day.
If you head into avalanche terrain today, utilize strict safety travel protocols, travel one at a time from safe zone to safe zone, only have one person on slope at a time, ensure all members of your party are carrying and know how to use beacons, shovels and probes, and avoid slopes with terrain traps.
