Avalanche Forecast for the Idaho City Mountains

Bottom Line

The likelihood of avalanche releases in the Idaho City Mountains is UNLIKELY. Pockets of poor snopack structure can be found, but they lack reactivity. 

The unabated inversion, with warmer temperatures above 7000', has continued to allow the snowpack to settle and sinter throughout. Snowpack is isothermal below 30 cm.

Snow surface on cold, sheltered, open slopes has varying degrees of surface hoar (ranging from 1 to 20 mm). Near-surface facets, known as NFS (recrystallized snow) from 10 to 20 cm in depth, have been observed under the surface hoar at most sheltered eastern and northerly slopes. These top 20-30 cm of recrystallized snow have significant cold content (generally below -10 °C).

The surface hoar and NSF will become worrisome weak layers once they are buried, as snow precipitation returns to our area.

Avalanche Problem #1:
Propagating (PWL) layers present on shady, sheltered north-facing slopes, above 7,200 feet.

Reactivity: Stubborn

Spatial Distribution: Isolated and Extreme terrain (ATES 2.0).

Avalanche release likelihood: UNLIKELY

Forecast Confidence:

High confidence.

Snowpack is rather uniform above 7,000 feet. An extended drought led to a relaxation of the snowpack. Only surface metamorphism is driving changes, with NSF development.

Snow and Riding Conditions:

Variable snow surfaces.

Facet skiing is found above 7000 feet on northerly aspects. Southerly aspects above 7000 feet have spring conditions. NE and SE aspects have a lot of instructional skiing, with varying degrees of solar crust.

Riding below 7000 feet is not recommended due to poor snow coverage.

ASG Snowpack Development Chart