Avalanche Observation : February 08, 2010
Date:
February 7, 2010 Observation Type:
Snowpit / Stability Observation
Route:
Long Lake in South Fork of Bishop Creek via South Lake
Weather:
Heavy snow in the early morning, tapering off by midday. Variable cloud with radiation and warming trend
Avalanche Activity:
Numerous small point releases in the new snow.
Appears to have not been a lot of wind associated with the storm at this elevation.
About 40cm of storm snow.Total snow depth of 185cm.
Dug a full profile pit on a west facing slope above South Lake.
Most west slopes have a melt freeze crust below the new snow that is readily felt by the ski pole and we wanted to look at this.
Pit showed two MF crusts at 137 and 128cm from base. Significant faceting around these crusts with crystals readily falling out. The failed in the SCT at 18 on the upper crust and SCT21 on the lower crust. Both were a Q2. The extended column test showed intitiation at 13 on the upper crust but no propagation within one tap of this.
Failure also occurred at a SCT26 at a very subtle density change below the two crusts at 115cm from bottom
Bottom 48cm of the pit were faceted depth hoar that was unconsolidated and weak, but under a lens appeared to rounding and moist.
Depth hoar in this area appears more developed and a thicker layer than I have seen in most of the Mammoth area.