At the mid and upper elevations, backcountry travelers could trigger recently developed persistent slabs on a variety of aspects. The likelihood of triggering these slabs will rise as snowfall intensity increases later in the day. Careful snowpack evaluation and conservative decision making will be essential for safe travel in avalanche terrain. Take note if you are hearing whumpfing or seeing shooting cracks; this is a very good indicator of unstable snow beneath you. With shallow snow depths and frozen conditions, avalanches are unlikely at the lower elevations.
Persistent slabs with depths up to three feet lie upon weak, faceted snow. In many areas, this fragile snowpack is further complicated by crust layers. Backcountry travelers could trigger these slabs on a variety of aspects above 7,500 feet. These slabs could also release on approach and propagate across terrain boundaries.
Another pulse of Pacific moisture and an associated cold front are expected to impact our forecast region overnight and through the day. Periods of heavy snowfall are likely after midnight and could continue until the cold front passes in the afternoon. Five to ten inches of new snow are possible in the mountains with the higher amounts likely to favor the Teton Range. The snowfall may mix with rain during the day at the lowest elevations before the cold front passes and the precipitation changes back to snow. Temperatures will be in the teens and 20s in the mountains and near freezing in the valleys.Winds will back from the south-southwest through the northwest to the northeast and are expected to increase to 25 to 30 with gusts to 45 miles per hour ahead and after frontal passage.The new snow will increase the load on a snowpack that has persistent instabilities. New soft surface slabs will begin to form in pockets on leeward aspects along the higher ridgelines. These slabs will become increasingly sensitive to human triggers as the day progresses. Persistent slabs with depth to three feet are a much more significant hazard and could be triggered by a single skier or rider or by a human triggered surface slab that steps down into the base layer of faceted snow. The general avalanche hazard is expected to be CONSIDERABLE and increasing with the new loading at the mid and upper elevations and LOW at the lower elevations where snow depths remain shallow.
