Tenki and Yuki Diary 4 Feb 08

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

Steep Deep Japan Hakuaba  weather data for the 24 hours to 7am for 860m asl Max temp -2C, min temp -10C.  -6C at 7am. Another 15cm of light snow , falling mostly in daylight hours yesterday.  More dense than the previous 15cm that fell the Saturday night:  51kg/m3  which equates to a blower 5.6% water.  Last night was clear allowing 1mm surface hoar to grow in the valley.  It will be bigger at tree line.

Field observations: Yesterday we travelled in the backcountry to 1550m asl.  The midday the temperature was -5.3C, moderate SW wind, consistent snowfall at about 2cm per hour.  My JAN weather and snow stability report can be found here.  I encourage people to use this valuable resource provided the Japan Avalanche Network.  By 1400hrs ski cut and natural size 1 avalanches were frequent and becoming quite dangerous when combined with terrain traps.  We left the area when it became obvious that instability was worse than just storm snow sluffing. 

During Sunday's storm several people were involved in an inbounds avalanche incident in Tsugaike ski resort in Hakuba.  Details in the SDJ Avalanche Incidents section.

The snow pack is currently unsafe for backcountry travel, and that includes travel in uncontrolled terrain in or next to ski resorts.

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