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The avalanche danger is MODERATE for WIND SLABS on southwest through north aspects at upper elevation. Strong winds on January 2nd have transported snow from windward locations to these aspects where triggering slabs up to 3 inches thick is possible. While the danger remains LOW below 3500 feet, small avalanches in isolated and extreme terrain are possible.
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Fri, January 5th, 2024 |
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. |
No Recent Avalanches.
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 |
Overnight moderate winds gusted on Marmot and Hatch peaks for 3 hours before tapering off in the upper elevations, which may contribute to the buildup of cohesive wind slabs. Throughout today expect winds to decrease as we accumulate a dusting of new snow. It will be possible to trigger a small wind slab avalanche in isolated locations near and just below ridgelines on SW to N aspects above 3500 feet. Although this avalanche problem may be stubborn in its sensitivity and unlikely to propagate, you may find specific locations where the slabs are thicker, more cohesive and rests on weak sugary snow.
Strong winds on the evening of January 2nd transported older soft snow onto leeward aspects, building thin and breakable wind slabs. These 1 to 3 inch soft slabs are easily penetrated by skis and boots and are mostly sitting on weak sugary snow on top of firm surfaces. For a period of 17 hours during this event Marmot weather station recorded winds of 28-34 mph while on Hatch Peak winds were 34-48 mph.
On or just below SW to N ridgelines it will be easy to find scoured and wind drifted snow surfaces. Recent wind has created more variable snow surface conditions including scalloping and sastrugi. Small near-surface facets formed during the last cold clear spell of weather creating a potential weak layer for future avalanches to slide upon.
To identify wind slabs look for hard snow sitting over weak snow, smooth and rounded or lens shaped features. They may sound hollow or crack out from your ski tip or snowmachine as you travel across them. Shooting cracks and whumphing are signs of instability and indicators of this avalanche problem.
Wind Sculpted Snow on Windward Ridgeline; Hatch Peak 3800 feet southeast Aspect 1/2/24
Hatch Peak Ridgeline 1/2/24
1-3 inch Wind Slabs on Skyscraper ridgeline 1/3/24
Cornices forming on Leeward Aspects in the Upper Elevation facing SW to N
Strong winds recorded at Marmot Weather Station on 1/2-1/3/24
Strong winds recorded at Hatch Weather Station on 1/2-1/3/24
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.