Hakuba Snow Report March 12th

As forecast the clouds came in yesterday and we had a light snowstorm go over…very light but better than the wetter kind. Tiny flakes are still whizzing around but nothing substantial really took off…though there was around 10cm of fresh it was pretty icy underfoot and didn’t get many if any powder whoops out of those on the resort.

Though snow is predicted it seems at this point it will continue much as it is now and clear up tomorrow afternoon. Rain is forecast Friday turning to snow as it cools slightly over the Weekend.

Snow Stability Information

There was 10 cm of new snow reported at Goryu Alps Daira; 1515m this morning and more is expected at elevation and in the Otari area. The new snow fell with strong winds from the west and changed to North west in the late afternoon. These winds have deposited the new snow on East and South east slopes over top of the existing surface crust to form a layer (March 10th crust layer) that will not be bonding to the new snow easily. Expect the new snow of varying depths to slide from this crust easily. Areas such as steep gullies and bowls will be retaining the most amount of new snow and may produce deep fractures that may propagate right across such bowls and gullies. Today’s solar radiation on these same lee slopes will add to rapid settlement and create an even more instability in the new snow. Northerly slopes may also be cross loaded and are expected to release at the March 10th melt freeze crust below.

Past melt freeze crusts may also become reactive with the weight of the new snow. Tests at tree line on Happo‚ 2200 m‚ produced easy to moderate results at the March 5th rain crust. See below for more test results. There is the possibility for step downs to older layers if slides in the new snow cause extra pressure on the weak faceted interfaces around the crusts deeper in the snow pack. The addition of wind loaded snow combined with possible mid day solar radiation twill increase the chance that slabs down to past melt freeze crusts and may propagate from shallow points near ridges and around rocks and trees on solar aspects. Be aware of what is going on down deep in the snow pack.

Snowpack Tests:

March 10th
Compression tests on a Northerly aspect of Nishi Hiodori @ 1900 metres a.s.l. found Hard results.
CTH(27‚23)B down 33cm
March 9th
Compression tests on a Southerly aspect of Happo One @ 2200 metres a.s.l. found easy results around a buried sun crust down 10 cm.
CTE/M(7‚11)SC down 10cm below sun crust.
Compression tests on a northerly aspect of Happo One @ 2200 metres a.s.l. found Easy to hard results that also had Sudden Collapse fracture characteristics.
CTE(1‚2)PC down 2cm; CTM/H(17‚21)RP down 38cm; CTH(24)SC down 47cm (all Crust and facet related)

March 8th
Compression tests on an Easterly aspect in the Tsugaike Seicho valley at 1800 metres a.s.l found very easy results just below the recent breakable rain crust at 11 cm.
CTE(1‚2)SC down 11cm on decomposing crystals size 2.
There were also Moderate compression‚ Sudden Planner results at the past storm snow / February 26th rain crust interface.
CTM(15)SP down 59cm on decomposing crystals size 1~2.
The layer to keep an eye on was much lower at 133 cms from the surface at the interface above the even older rain layer that is still retaining heat and a lot of moisture and has mixed forms of facets and decomposing snow right above it. There were varying results on this layer from easy shovel shear tests to moderate and hard sudden planner results from compression tests. This is definitely a layer to keep an eye on as if it goes on this one‚ expect a very large and destructive slide.
CTM/H(20‚23)SP down 133cm on mixed forms and facets over a thick rain layer

Travel Advisory:

Avoid solar radiated lee slopes in avalanche terrain. Avoid steep gullies‚ bowls and wind loaded slopes. Possibility of triggering avalanches in in the past storm snow in certain terrain such as‚ steep lee slopes or cross loaded gullies and cliff bands. All slopes will be reactive and you should expect slab avalanches to the now buried March 10th rain crust. Keep travel to low angle supported slopes and be careful of run outs from above.

Avalanche Hazard Rating:

Below Tree Line: Considerable (limited snow accumulation)
Tree Line: Poor
Alpine: Poor

Grauple over riding crust
Surface avalanches in new snow due to Grauple layer over riding ice layer
Increased snowfall adding load to buried week layer
Steadily increasing air temperature
Cornice fall
rapid settlement of surface snow causing load on buried weak layers
Warming of surface snow causing instability in surface and near surface layers
Solar radiated cornices becoming weak with direct solar radiation.
Use caution if crossing solar radiated slopes.
Increased caution advised around rocky outcroppings‚ cliffs and well spaced trees in start zones.
Windward scouring of ridges and rock out-crops creating uneven loading of slopes
Due caution on cross loaded slopes
Poor bonding at or around buried crust
Facet layer around buried crust
Wide propagation due to wind slab
Stay away from steep and convex terrain

Danger level 4 : High

Natural and human triggered avalanches likely.
Danger level ratings are set for conditions at tree line
and may vary from below tree line and High Alpine areas.
Use this information as a guideline only.