Super warm yesterday but as forecast the temperature dropped in the evening and by this morning those slushy pools of water were slippery sheets of ice ready to slip the unprepared and the soft lumps of snow hard ice balls ready to penetrate the most toned of butts. No real snow in the valley overnight though early this morning a dusting started to fall leaving enough to paint the cars just white.
Good temperatures this morning with -7 measured at 1800m and -4 at 800m with the Happo Pond weather station measuring -15 degrees (compare that to the -2 yesterday) and light SE winds. Runs will be groomed and the snow should be in a variety of states from top to bottom.
Snow is forecast through today, easing overnight and continuing tomorrow with possible lows of -12 overnight.
SNOW STABILITY INFORMATION AS AT FRI 23RD:
Last nights rain in the valley and today’s very warm temperatures produced very heavy and moist surface snow up to 2000 m on solar radiated aspects. What was rain in the valley fell as snow from 1000 m and higher elevations. The height of new snow at 2000 m on North aspects in the Goryu area was 15 cm and 10 cm at 1500 m.
Multiple size 1- 2.5‚ loose avalanches were observed on all solar radiated aspects between 1200 m and 2600 m in the Hakuba mountains. These loose slides were releasing in steep‚ convex terrain from rock outcrops‚ trees and under cornices. Two ski triggered loose slides size 1.5 on the North aspect in steep (40 degree)‚ sparsely treed terrain.
Tests on North aspect terrain in the Goryu area at 2000 m found easy compression tests with sudden collapse fracture characteristics down 15 cm at the new snow / melt freeze interface that was created by yesterday’s warm mist up to 2000 m. This weak layer also produced a moderate result in an Extended Column Test as well as a Reuch Block Test; RB4. The Grauple layer that has been reactive over the last week is showing greater bonding and consolidation. Tests on this layer were producing hard results and only producing breaks. One RB6 was produced.
Beware of cornices and avoid steep convex terrain below rock outcrops‚ areas of sparse trees and below cornices on lee slopes at all elevations. Caution as forecasted snow tonight and tomorrow will put greater load on the present weak layer on shaded aspects as well on wind loaded steep lee slopes and gullies. New snow on South faces should bond to the rough surface of the multiple point release avalanches of today but will be sliding off areas that did not slide as there will be a very hard sun crust underlying the new storm snow. Be extremely careful if the new snow falls as grauple at the on set of the storm.
Avalanche Danger will increase with the addition of new snow and increased wind.
Increased snowfall adding load to buried week layer
Radiative cooling of snow surface causing low density snow and frost at surface
Extreme radiation and warming of southern exposures
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.
Due caution on cross loaded slopes
Poor bonding at or around buried crust
Facet layer around buried crust
Stay away from steep and convex terrain
Danger level 3 : Considerable
Natural avalanches possible. Human triggered avalanches probable.
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.