Mt Shasta Avalanche Center - Shasta/Trinity Nat'l Forest

Last night (Jan. 1), 1-2 inches of new snow fell (.1" SWE). The new snow fell on top of a zipper crust formed by a warm day and subsequent nighttime freezing. Below the crust, nearly a foot of fist (F) to four finger (4F) hardness snow exists, resting on several old crusts to the ground. Total snow height was 29.5 inches. We dug a pit on the southeast flank of Casaval Ridge, near treeline. A weak layer of snow was found 18 in / 45 cm down from the surface.

Variable winds, active riming on trees and structures.

Old/new interface (12/10 @75cm) produced SP fractures and inconsistent propagation. 12/10 was the culprit in recent small (D1.5) human triggered avalanches in the hwy 542 corridor on northerly aspects above 5500ft. 12/10 is rounding and gaining strength. 11/23 (@50cm) is moist, rounding, and not an issue.

Recent HST doubled HS. HST is well bonded to old snow surface (12/10 @50cm) below 5000ft. 11/23 (@20cm) is moist, rounding, and not an issue.