Observation: Public

Observation Details

Observed Avalanches

Signs of Unstable Snow

Observations

Traveled up Lanham Creek to Lanham Lake under clear skies and cold temperatures, departing the car around 0915. Temps rose slightly by mid morning as we climbed to a high point west of Lanham Lake where standing in a direct sun was quite comfortable. We dug a pit at this location (see below) and descended back to the lake through debris and tree bomb laden surface conditions, at which point we elected to travel south to the head of the drainage in search of less solar affected snow. Near the col at the head of the drainage we dug another pit (see below) and then continued on to the col and up to a high point around 5900 feet. We briefly traveled onto a S/SE slope at this point, which harbored a breakable sun crust and findings of radiation recrystalization. Skies remained clear at this point in the day (1600) and from this point we observed the hard slab from 2/12 on Jove, an older hard slab in the vicinity of some glide cracks on Big Chief (5200 feet, east aspect) and what appeared to be a newer glide crack around 4500 feet, E/SE aspect on Big Chief as well. We had excellent views into the Chiwaukum, and did not note any obvious new avalanches in this zone. Throughout the day, winds were at most calm out of the west. There was evidence of subtle wind effect though no pronounced wind slab formation in terrain we traveled in. We skied/rode mostly treed terrain and lower angled open terrain.

Pit #1:
5466', E aspect, HS 220cm
CT12 down 23 (interface of new storm snow from 2/13), failing on faceted snow underneath a well developed crust from the warming event Sunday 2/12.
CT21 down 95 (presumed to have failed on facets underlying MLK crust)
ECTN10 down 23
PST44 (end) down 95 (failing on facets below MLK crust)
PST44 (end) down 95 (failing on facets above MLK crust)

Pit #2:
5600', E/NE aspect, HS 275cm
CTV down 25 (interface of new storm snow from 2/13, failing below a well developed crust from the warming event on Sunday 2/12)
CT5 down 25 (interface of new storm snow from 2/13)
CT21 down 105 (decomposing facets on a crust, 5cm below what we believe to be the MLK crust)
ECTN12 down 25
PST44 (end) down 1m on MLK crust

Per the above pit results we hypothesize that the new/old snow interface will likely become problematic with a potential incoming larger storm later this weekend/early next week. We additionally observed well developed surface hoar grains in the valley bottom and sheltered polar aspects which could also lend to future instabilities. We also agreed that attention should continue to be paid to the MLK crust given its surrounding structure and our corresponding stability test results.