Regione Autonoma Valle d' Région Autonome Vallée d'Aoste Assessorato opere pubbliche, difesa del suolo e edilizia residenziale pubblica Assessorat des ouvrages publics, de la protection des sols et du logement public Dipartimento difesa del suolo e risorse idriche Département de la protection des sols et des ressources hydriques Assetto idrogeologico dei bacini montani Aménagement hydrogéologique des bassins versants Ufficio neve e valanghe Bureau neige et avalanches Snow and avalanche Bulletin n° 32 issued on 02/06/2015 at 04.00 p.m. valid 72 hours out of controlled and open ski runs - Next update on 02/11/2015 GENERAL CONDITION New snow and wind - slabs hard to detect and therefore to be avoided!

Snow height [ cm ] Ta Continuous Ground level New [°C] Last Last snowcover above h 07.00 h 07.00 h 48 h 07.00 snowdrift event snowfall [m a.s.l.] 2000 m 2500 m 2000 m 2000 m Shady Sunny A - Central Valle d’Aosta 40-100 90-120 5-25 -4 °C 02/05/2015 02/06/2015 valley floor valley floor moderate/strong from E B - Gressoney, Ayas, 40-110 120-190 40-60 -3 °C 02/06/2015 02/06/2015 valley floor valley floor Champorcher Valleys moderate/strong from E C - Rhêmes, , 60-90 70-120 15-30 -5 °C 02/05/2015 02/06/2015 valley floor valley floor Valleys moderate/strong from E

D - Alpine ridge 50-110 60-210 5-15 -5 °C 02/06/2015 02/06/2015 valley floor valley floor moderate/strong from E New snow in the . More intense in the Champorcher, Gressoney and Ayas valleys. Estern winds have created and continues to create new accumulations. The snow has a structure favorable to avalanche releases because the surface layer is heavier and compacted (wind, humidity, increasing temperatures) and rests on softer layers. Any avalanches, spontaneous or artificial, in their run may also involve the deeper layers of the snowpack and thus they can achieve medium and large size. The avalanche hazard level is 4-strong in the Gressoney, Ayas and Champorcher valleys, where this last snowfall was more abundant (40-60 cm of fresh snow in the valleyfloor, 60-80 cm with wind over 2400 m). The avalanche hazard is 3-considerable in the rest of the Region, with special attention to the Cogne, Pila, Mont Avic and Clavalité areas (30 cm of fresh snow with wind). Reports of avalanche releases: in the B area, during the artificial bombing in the ski-resort, slopes below 35° come off very easily with 20-50 cm thick slab avalanches flowing very quickly. Also full-depth slab avalanches of medium size, mainly at the west and north aspects were released. The very steep slopes (>35°) have purged spontaneously (partial information due to poor visibility). Attention - Champorcher, Gressoney and Ayas Valleys: FORECAST 80 cm of new snow + wind = new and widespread unstable windslabs Saturday 02/07/2015 The avalanche danger is forecast at 3-considerable on the whole Region. Saturday: sun, moderate easterly winds and rising temperatures will cause an intense natural release with numerous sluffs from all the very steep slopes near the rocks, especially those exposed to the south and west. Mid-sized avalanches are possible from usual gullies and, in individual cases, even large, able to reach the valley floor, especially in the valleys of Champorcher, Gressoney and Ayas. Sunday: beautiful sunny day and then during the hottest hours a natural release activity is expected again. The key factor to consider will be the arrival of foehn wind. In addition to the creation of new accumulations (this time on south slopes) it can cause a sudden warming of the snowpack. Trend for Monday: slow improvement of stability.

Artificial release avalanches: the snowpack is still very unstable, especially because of the recent wind accumulations extremely weak. Triggering is possible even by a single skier/hiker. The most dangerous places are the areas near ridges, gullies, valleys and slope changes. In recent days the winds often changed direction and therefore are visible only the last accumulations, while the older ones are difficult to detect. In the Champorcher, Gressoney and Ayas areas the main problem are the newer accumulations, very thick (well over 1 m). Everywhere it remains the risk of trigger the deeper weak layers; then you have to pay attention to the transition zones between much and poor snow. Sunday 02/08/2015 Monday 02/09/2015

KEY Critical slopes altitude and aspects Rising avalanche danger during the day Hazard scale 5 VERY HIGH 4 HIGH 3CONSIDERABLE2 MODERATE 1 LOW Answering service: snow and avalanche Bulletin +39 0165 776300 - Weather Bulletin +39 0165 272333 For an accurate interpretation of the Bulletin, a specific guide is available at www.aineva.it/guida.html Friday 02/06/2015