Bluebird in the morning yesterday, the clouds came in in the afternoon and some strong North-Westerlies came up but there was still some untapped powder to be had. Some snow fell yesterday evening but left only 5-10 cms in the valley this morning. Goryu reported 15cm fresh snow this morning so powder out there for some.
It was a cold one this morning measured at -10 at 1800m and its currently -6 in the valley. The winds at the top of Happo have shifted to the South but aren’t blowing too hard this morning. The low weather system seems to have passed us and is sitting over Hokkaido now. Glad we got our share…
SNOW STABILITY INFORMATION:
The sun crust of January 4th is still proving to be a weak layer now under 20 – 90cm of wind affected new snow. Facets were found above and below the crust Sunday in 3 pit locations all dug on solar aspects in the Tsugaike shizen during the Evergreen Outdoor Center Avalanche Safety Training course. Compression tests found easy results in the top wind affected new snow and moderate results just above the crust with the new lighter snow not bonding to what might be buried surface hoar or developing facets. There is still the Dec 23rd rain crust is also still a concern as we receive more snow and today’s strong solar radiation puts extra stress on those lower layers.
AVALANCHE OBSERVATION: 1 large slab avalanche that appears to be a size 3 has ripped out on the South face of Happo One next to the Grat Quad lift. The Crown fracture appears to have propagated out 100 metres plus at a crown height of about 60 cm. This is proof that the new snow that is over riding the Sun crust is still very reactive and the probability of natural avalanches is high. BE VERY CAREFUL of solar radiated exposures in lee areas and cross loaded bowls and gullies.
Be extremely careful of entering into lee slopes from scoured ridges or convex terrain and around warming rock bands.
Areas of deep snow pack will have greater stability than the thin shoulders and areas where overnight radiation of heat has created near surface faceting and faceting crystals around the areas of shallow crust. Big alpine bowls may be slow to stabilize and may propagate very wide due to the very tensile nature the present wind effected alpine snow pack.
Continued caution around cornices should be practiced and these areas avoided all together. CORNICES ARE VERY FRAGILE in today’s solar radiation!
Suffocation by falling face first in to deep powder
High danger of falling snow from rooves
High density new snow over lower density snow layer
Increased snowfall adding load to buried week layer
Steadily increasing air temperature
Radiative cooling of snow surface causing low density snow and frost at surface
Rapid air temperature increase
rapid settlement of surface snow causing load on buried weak layers
Falling tree bombs (Possible triggers and cause of avalanches as well as overhead hazards)
Extreme radiation and warming of southern exposures
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 instability of solar aspect start zones especially under cornices and very steep slopes.
Increased caution advised around rocky outcroppings‚ cliffs and well spaced trees in start zones.
Lee side loading
Windward scouring of ridges and rock out-crops creating uneven loading of slopes
Due caution on cross loaded slopes
Surface hoar frost created overnight
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.
TEMPERATURE IN THE VALLEY: -6
TEMPERATURE AT 1800m: -10
BASE DEPTH (GORYU):
220 cm at 1800m
90 cm at the base