Observations have been very limited and there is a lot of uncertainty about how the ongoing storm and rainfall are affecting the snowpack, so a cautious approach is advised. It is recommended to avoid steep rain-soaked areas at lower elevations and watch for new storm slab formation at the highest elevations, especially in wind-loaded terrain.
If you're out in the mountains, please consider submitting a MIN and let us know what you're seeing.
As freezing levels have dropped, the storm precipitation has likely switched from rain to snow at higher elevations. New slabs may be forming over a crust and/or the rain-soaked snow surface. Watch for signs of new slab formation, especially in wind-loaded terrain at higher elevations.
Rain has likely soaked the snow surface at most elevations. Use extra caution on all steep slopes while it is raining or where the snow surface is wet.
On Sunday, observations remained limited but included several size 1 loose wet avalanches and a size 1.5 wet slab avalanche.
On Saturday, limited observations during the storm included numerous natural loose wet avalanches up to size 1.5 and several natural slab avalanches up to size 2. These slabs were up to 40 cm thick and were typically releasing at around treeline elevation. Some of these slabs were triggered by loose wet avalanches in motion.
Rain has recently soaked the surface at all elevations. As freezing levels dropped on Monday, a new surface crust is expected to have formed. With lower freezing levels and ongoing precipitation, snowfall is expected to be burying the wet surface and/or surface crust.
Before the rainfall, new storm snow buried a highly variable old surface which included an unsupportive sun crust on southern aspects, spotty surface hoar in sheltered terrain, and heavily wind-affected surfaces in wind-exposed terrain.
A layer of decomposing surface hoar crystals could be found down 70 cm prior to the storm. There is also a layer of weak, sugary facet crystals near the base of the snowpack. During recent testing, both of these layers were producing hard results and there have been no recent reports of avalanches occurring on these layers. However, the current storm loading will test these layers and there still remains potential for avalanches in motion to step down to these older layers.
Overall, the snowpack continues to present as thin and averaged 130 cm deep at treeline prior to the storm.
Monday night
Precipitation up to around 40 mm, strong to extreme SE-S wind, freezing level around 1200 m.
Tuesday
Precipitation 5-15 mm, strong S-SW wind, easing in the afternoon, freezing level reaching around 1700 m.
Wednesday
A mix of sun and cloud, moderate W wind, freezing level 800-1000 m.
Thursday
Precipitation 5-15 mm, moderate to strong S-SW wind, freezing level around 1000 m.
More details can be found in the Mountain Weather Forecast.
