Tenki and Yuki Diary 10 Feb 08

Know the weather = know the snow pack = know the stability.

Steep Deep Japan Hakuba  weather data for the 24 hours to 7am for 860m asl Max temp 3C, min temp -12C and  +2C at 7am. 6cm of new snow, very heavy 106kg/m3, equivalent to 11.6% water   Barometer trending upwards.

Field observations:  Yesterday we travelled in the backcountry to 2200m asl in the Tsugaike BC area. After a rare sunny start to the day I recorded -10.9C around midday and the winds were above 30kph from the WSW with moderate snow transport onto northerly aspects.  Snow was falling at 2cm per hour.  At around 1600m-1900m asl south aspects again revealed a deeper more stable snowpack, same as was found in the area a few days earlier (see north versus south snow pit comparisons taken on the same day).  North aspects on loaded rolls were producing shooting cracks after the application of several jumps in a weak area.  The rain crust is also far more prominent on the northerly entrances to lines than on the southerly terrain below the ridge.

On entrances to SE aspect lines at 2200m asl we found a hard 35cm wind slab sitting on top of a soft snow layer.  In compression tests this slab was consistently failing after 4 taps from the wrist, ie. CTE(4).  We chose not to ride this slope as a result and took a conservative routes out of the area.

Please also refer to the Hakuba backcountry travel advisory from the guides at Evergreen Outdoors.