March 19, 2014 Observations from a tour in the Central Flathead Range:
Objectives: to investigate the snowpack above the most recent rain/snow lines (3/14 and 3/16), search for deeper crust/facet combos, recent and older wind slabs and/or other instabilities; and find fun, reasonably safe skiing.
Camped at 2100 meters on night of 3/18. Weather that afternoon had included periods of intense snow showers (up to 3cm/hour) with light and variable winds. Temp at 17:00 was -6 degrees C. Trailbreaking had been arduous above 1860 meters, where the last Sunday’s storm had dumped 30 plus cm of dense snow and a similar amount had fallen Monday through Tuesday. Below 1650 meters trailbreaking had been easy, with 10-15 cm of new snow on top of a supportive crust. (Below the crust was isothermal mush.) Climbed on low-angle N-facing slopes in the trees and experienced no whumpfing or cracking. Above 2100 meters trailbreaking was considerably easier in lighter density snow.
Saw no evidence of recent natural avalanches on wind-loaded terrain near Mount Adams, peak 7798, or anywhere else, except for small sluffs on steep solar-affected slopes. (On descent, at 17:15 observed a small recent natural avalanche at 2000 meter elevation with a crown 10-15 cm deep and 30 meters wide that ran 30 meters. This was on a 38 degree rollover in a NE-facing gully that has a substantial wind-funnel/fetch immediately above it. (See attached photos.)
@ 11:30 am @ 2235 meters: -10 degrees C. Partly cloudy. Gusty SW winds up to 10m/s.
Observed moderate snow transport onto N through E facing slopes at my location, though big snow plumes were visible off the higher peaks, and wind loading was apparent in an adjacent NE-facing corniced bowl. (photo)
Test Profile info:
NW-facing 35 degree slope near the ridgetop at 2235 meters.
H.S. Excavated down 200cm, and buried a 240cm probe below that without hitting ground.
Boot penetration: 75cm. Ski penetration: 32cm.
Hardness, measured from the surface: 0-40cm: F; 40-70cm: 4F; 70-110cm 1F; 110-200cm P. (photo)
Did not find rain crusts in top 200cm of snow. Did find a few density changes not revealed in hand hardness tests. (photo)
2x CTE @ 20cm Q3 (scores: 5 and 7)
2x CTH @ 40cm Q3 (scores: 24 and 25)
ECTN 10 @ 20cm
Ski cut small moderately wind-loaded rollovers up to 40 degrees with no results.
Skied NW through N-facing wind-sheltered slopes up to 35 degrees without incident. Skiing quality was excellent.
At 2100 meters it was -6 degrees C and snowing at 1cm/hour with moderate SW winds at 17:00
At 1160 meters it was 2 degrees C and snowing at less than 1/cm per hour at 18:00.