Avalanche Forecast
Issued: Jan 18th, 2019 5:14PM
The alpine rating is Storm Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeStorm slabs are building above a touchy weak layer. Be extra cautious around steep rolls and wind loaded slopes.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
FRIDAY NIGHT: 5-15 cm of snow, strong southwest wind, alpine temperatures drop to -8 C.SATURDAY: Flurries easing throughout the day with another 5 cm of snow, strong southwest wind, freezing level climbing to 1300 m, alpine high temperatures around -3 C.SUNDAY: Light flurries in the morning then clearing in the afternoon, moderate north wind, freezing level climbing to 1000 m, alpine high temperatures around -5 C.MONDAY: Mix of sun and cloud, light northwest wind, alpine high temperatures around -8 C.
Avalanche Summary
Slab avalanches will become more likely as snow accumulates above the freshly buried weak layer. The key is watching for signs of this new slab becoming reactive, such as cracking, whumpfing, or stiffer deeper pockets of snow.On Thursday, when there was only about 10 cm of new snow, skiers triggered fast moving sluffs (loose dry avalanches) and small wind slab avalanches on north and east facing slopes. A skier also remotely triggered a size 2 wind slab (60 cm deep) on a southwest alpine slope.
Snowpack Summary
By Saturday, 15-30 cm of snow will have buried a layer of large surface hoar crystals and sun crusts. This will create the potential for fast moving sluffs and thin slab avalanches with wide propagations. The most suspect terrain features are steep slopes and rolls below 2000 m (where the largest surface hoar exists) and steep south-facing slopes in the alpine (where sun crusts exist).The middle and lower portions of the snowpack are generally well-settled and strong. Professionals are tracking a layer around 130 to 180 cm deep, composed of weak faceted grains, surface hoar, and a sun crust. The chance of triggering this layer is low. In shallow snowpack areas, the base of the snowpack may also still be composed of weak faceted grains.
Problems
Storm Slabs
New snow is gradually accumulating above weak surface hoar and/or crusts. Touchy slabs can be expected in areas with more than 20 cm, such as wind loaded slopes.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Watch for whumpfing, hollow sounds, and shooting cracks.Be cautious of sluffing in steep terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 19th, 2019 2:00PM