Monthey-Val d'Illiez

Snowpack

After two weeks without any significant precipitation, this week began with a blanket of snow, particularly on shady slopes above approximately 2800 m and in general in glaciated high Alpine regions. The fresh snow from the last few days has been deposited on steep shady slopes, in places on a crusted snowpack surface and in others on a faceted surface. With fresh snow and moderate to strong southwesterly winds, accumulations of drifted snow, some of them prone to triggering, will develop on Wednesday, especially in the west and in the high Alpine regions.

OutlookThursday

Conditions will be mostly cloudy with widespread precipitation. The snowfall level will rise to between 2600 and 2800 m during the night to Thursday and drop to between 1600 and 2000 m from the north-west over the course of the day. In the west and on the main Alpine ridge, 20 to 40 cm of snow is expected in the high Alpine regions and up to 60 cm on the border with France. The southwesterly wind will be strong to storm-force at high altitudes and moderate to strong in the south.

The danger of dry avalanches will increase at high altitudes in regions exposed to precipitation. Below approximately 2800 m, wet snow slides are to be expected where precipitation falls as rain. Experience in assessing avalanche risk is necessary.

Friday

Temperatures will fall significantly, with snowfall, probably heavy in the Lower Valais and on the northern Alpine ridge, becoming widespread above approximately 1400 m. There will be strong westerly to north-westerly winds. Conditions will be mostly sunny in the south.

The risk of dry avalanches will continue to increase, especially in the west and north, even at high altitudes. The situation will become increasingly wintry. In the high Alpine regions, touring conditions will be critical, especially in the north and in the Valais. Experience in assessing avalanche risk is necessary, as is restraint. The risk of wet avalanches will decrease as temperatures fall.