Observations from Stevens Peak

Snow profile to assess snowpack several days after large R4D3 natural avalanche (tracks in area from same timeframe are possible remote trigger, but not survivable as direct trigger). Although debris still appears angular, 2-5cm of snow was on top of debris, indicating avalanche occurred late day on Sunday 02/09 or Monday 02/10. Debris from same start zone (pic 1) ran into two distinct drainages and ran for up to a mile in one and just less in the other - in both paths crossing 200-300 meters of very low angle terrain before continuing into steeper traditional avalanche terrain. Pic 2 taken from halfway down larger path, with start zone visible just climber's left of summit buttress ("Thumb" rock visible in both pic 1 and 2 for scale). Although start zone was down to rocks indicating basal failure, the bed surface in each track measured ~100cm from ground. No weak layer was observed at a similar height in snow profile, although two temperature changes were observed at heights close to 100cm. Profile dug at 9100ft in near treeline terrain adjacent to start zone (pic 1 taken from profile site). Pic 3: 3mm angular basal facets which showed Sudden Collapse on 2x Deep Tap tests beyond the 30 loading steps. Probing bed surface showed similar basal weak layer, yet neither path slid to the ground beyond start zone.