Gruyère

In the west and in the north a considerable avalanche danger will be encountered over a wide area.

The fresh and older wind slabs represent the main danger. They are only small but in some cases prone to triggering. Even a small avalanche can sweep snow sport participants along and give rise to falls.

Avalanche bulletin survey: intermediate levels - helpful or confusing? Link to the survey in AvaBlog (on SLF-App WhiteRisk or at slf.ch)

Snowpack Fresh fallen snow and freshly generated snowdrifts lie deposited on shady slopes over widespread areas on top of an unfavourably layered old snowpack surface. Avalanches in those locations can be easily triggered or else trigger naturally in the major areas of precipitation. On sunny slopes the old snowpack surface was significantly more favourable. On the northern flank of the Alps on north-facing slopes, in addition, there are expansively metamorphosed (faceted) layers deeply embedded inside the snow cover in some places. In the southern Valais and in Grisons on north-facing slopes the entire snowpack over far-reaching areas is expansively metamorphosed (faceted) and loosely-packed. In the southern Valais in particular, avalanches can fracture down to deeply embedded layers of the snowpack and subsequently grow to large size. Observed weather review Thursday, 09.03.2023 During the nocturnal hours in the western and the northern regions more than anywhere else there was precipitation over widespread areas. The snowfall level lay between 1500 and 2000 m. During the daytime hours it was quite sunny. Fresh snow Between Wednesday midday and Thursday morning the following amounts of fresh snow were registered above approximately 2200 m:

• western part of Lower Valais, northern part of Valais, Binntal, Goms: 25 to 40 cm;
• remaining parts of Valais, remaining parts of the northern Alpine Ridge west of the Aare, Bedretto, upper valleys of Maggia: 15 to 25 cm;
• remaining parts of the northern flank of the Alps: 5 to 15 cm; in the remaining regions of Switzerland less, or else it remained dry.

Temperature At midday at 2000 m, 0 °C in the northern regions and +3 °C in the southern regions. Wind Winds were blowing from westerly directions,

• at strong to storm strength in the western and in the northern regions during the nighttime hours;
• in the other regions of Switzerland, predominantly at moderate to strong velocity.

Weather forecast through Friday, 10.03.2023 Precipitation is anticipated over widespread areas which in the western regions will be intensive. The snowfall level is expected to descend from 1600 down to approximately 1200 m. In the southern regions it will be partly sunny during the daytime. Fresh snow Between Thursday evening and Friday afternoon the following amounts of fresh snow are expected above 2000 m:

• northern and furthermost western parts of the Lower Valais: 25 to 40 cm;
• Vaud Alps, remaining parts of Alpine Ridge west of the Reuss, remaining parts of the Lower Valais: 15 to 25 cm;
• remaining parts of the northern flank of the Alps, remaining parts of Valais: 5 to 15 cm;
• in the other regions of Switzerland, only a few centimetres.

Temperature At midday at 2000 m, -2 °C in the western and the northern regions, and 0 °C in the southern and the eastern regions. Wind Winds will be blowing from westerly directions,

• at strong to storm velocity in the northern regions and in general at heightened altitudes;
• in the other regions of Switzerland blowing generally at moderate strength.

Outlook through Sunday, 12.03.2023 By Sunday afternoon in the western and the northern regions, further rounds of precipitation are anticipated. In the Valais as well as in the western and central sectors of the northern flank of the Alps, approximately 30 to 50 cm of fresh snow is expected; in the other regions, less. The snowfall level will lie between 800 and 1500 m. As Saturday approaches, Danger Level 4 (high) could be reached in parts of the Valais as well as in the northern Alpine Ridge west of the Reuss. In some places, large-sized avalanches are expected to trigger naturally, even very-large sized avalanches in the furthermost western part of Lower Valais. There, exposed transportation routes can be placed at risk. On Sunday the frequency of naturally triggered avalanches will decrease as precipitation slackens off. In the southern regions and in the inneralpine regions of Grisons, avalanche danger levels are not expected to change significantly.