Northwest Coastal

Fair - Forecast snowfall amounts are uncertain

Monday: A low pressure system over Gulf of Alaska hits the region. Precipitation heavy (20-40 mm) accompanied by strong-extreme ridgetop winds from the NW. Alpine temperatures rising  to -2.0 and freezing levels near 700m. Tuesday: An intense warm front will continue to bring moderate-heavy precipitation (15-30 mm). Ridgetop winds will switch and blow strong-extreme from the West. Alpine temperatures near -1 and freezing levels up to 1200 m.  Wednesday: An upper ridge continues to build generally bringing dryer conditions during the day. However, light precipitation is expected to persist in the evening. Alpine temperatures near -3.0. Ridgetop winds blowing form the SW in the light ranges.

Natural sluffing has been reported from steep terrain features. On Saturday, numerous size 2.0 natural slab avalanches were seen at treeline elevations from steeper terrain features. Treeline and below treeline storm slabs have shown a weaker bond to the crust buried below. Active avalanche control work done on Friday concluded 1.5-2.0 slab avalanches at all elevations.

Recently, the region has seen 30-70 cm of new snow which continues to build over a variety of surfaces. These include old hard and soft wind slabs, scoured slopes, blue ice, thin melt-freeze crusts and surface hoar. Moderate to strong winds are shifting snow into slabs in the lee of terrain breaks such as ridges and ribs. Reports generally indicate that the bulk of this storm snow seems to be settling quickly, which is a good. However, with a continued stormy pattern I would wait out the storms and watch how the snowpack adapts to the rapid changes.Two persistent weaknesses (comprising of surface hoar and facets) buried in the upper snowpack recently gave moderate to hard, sudden results in snowpack tests. The mid and lower snowpack is generally well settled and strong, although basal facets remain a concern in the north of the region.