South Columbia

Touchy and growing storm slabs will keep avalanche danger elevated this week. Riding should be great, but a conservative approach is recommended. Stick to simple terrain.

Moderate - Forecast snowfall amounts are uncertain

Tuesday: Periods of snow 10-15 cm. The freezing level is near 1400 m and winds are moderate to strong from the SW. Wednesday: 10 cm of snow should accumulate before tapering off throughout the day. The freezing level is near 1400 m and ridge winds ease from moderate W-NW to light. Thursday: Periods of snow. The freezing level remains near 1400 m and wind increase to moderate from the SW.

Numerous intentionally-triggered size 1-1.5 storm slabs were reported on Sunday. Most of these were from unsupported and wind-loaded features. Additionally, there were reports of loose dry sluffing in steep terrain, and a couple natural size 2 storm slabs from big alpine slopes. These fresh storm slabs should increase in size and likelihood and become much more widespread as they build throughout the week.

30-40 cm of new storm snow sits on a crust on solar aspects and lower elevation terrain, and surface hoar on shady and sheltered slopes. Touchy new wind slabs are likely in exposed lee terrain at and above treeline. A weak layer of surface hoar and/or a sun crust buried February 21 is now 40-75cm below the surface. Where it exists, this layer may become reactive to human triggers as the overlying slab develops. The surface hoar and/or crust layer buried February 10 is now down 75-120cm. This layer was less reactive over the weekend with cooler temperatures, but remains a concern for large triggers like cornice falls or a smaller slide in motion. Cornices are large and potentially weak and should be avoided if possible.