Know the weather = know the snow pack = know the stability.  For previous weather and snow reports use the Diary link at the top of the page.

Steep Deep Japan Hakuba  weather data for the 24 hours to 7am for 860m asl. Max temp +7C, min temp -4C and  -2C at 7am. 1cm of new snow  in the last 24 hours.  Depth of snow 196cm after settlement.  Barometer is steady at 908mbar.  The sky is has about 90% cloud cover with moments of filtered sunlight.  Snow settlement has been dramatic:  30cm in 3 days.  Correlated with that is the 10cm snow temperature hitting zero for the first time this season.  Spring is coming.

Field observations:  Yesterday we travelled in the backcountry to 2000m asl and observed NE and S aspects.  The previous evening brought 4cm of snow polluted with dust from deserts in China (Gobi?).  This is a seasonal event.  The noticeably brown snow absorbs sunlight and heats the top of the snowpack producing a very sodden layer.  Yesterday was very warm and sunny in the morning and the results on the dark snow were disastrous.  In the afternoon it clouded over and started to snow at 2-3cm per hour at 2000m asl.  Sunlight penetrates about 30cm into the snowpack surface and therefore any new snow less than that depth will not stop the solar radiation from heating the dark buried snow, thus causing all new snow to turn to warm water mush.  We need a large snowfall to cover the dust layer, which will in turn become a dangerous ice layer. 

Our observations of steep protected north facing slopes revealed intense faceting about 40cm deep, with a warm temperature crust at about 50cm, beneath that crust was 4-5mm facets and pockets of well formed goblet shaped depth hoar.  In short, steep protected north aspects in the Goryu area have very little structural support in the deeper snow pack and are inherently unstable as a result.  We chose not to ride such a slope after having set out with the intention to do so (steep = more than 45 degrees)

As usual my snow stability report is posted on Japan Avalanche Association (JAN) can be found here.  JAN have made available a valuable public resource that I encourage people to consult before entering the backcountry.

Please refer to the Hakuba backcountry travel advisory from the guides at Evergreen Outdoors. (Frequency of update is unreliable)