Bisistal

High avalanche danger will be encountered in some regions

High avalanche danger will be encountered in some regions

Large quantities of fresh snow and the wind-drifted snow are lying on the unfavourable surface of an old snowpack in particular on west, north and east facing slopes. Natural avalanches are to be expected. These can reach large size in particular on north and east facing slopes. The danger exists in particular in alpine snow sports terrain. Transportation routes situated at higher altitudes can be endangered in some cases. Backcountry touring and other off-piste activities call for extensive experience in the assessment of avalanche danger and great restraint.

Fresh snow and strong winds from the west to northwest are giving rise to extensive snow drift accumulations in the regions exposed to heavier precipitation. Large amounts of the fresh snow are being transported in the other regions as well. On west, north and east facing slopes sheltered from the wind, the large quantities of fresh snow are lying on an unfavourable faceted old snow surface. In the Jura, on the northern flank of the Alps and in western Lower Valais, sometimes thick rain crusts dating from the final week of the old year exist deeper in the snowpack up to high altitudes. In these regions the thick crusts are stabilising the base of the snowpack, so that avalanches are unlikely to release the deep layers. From southern Valais through northern Ticino to Grisons, in contrast, in many cases the entire snowpack is faceted and interspersed only with thin melt-freeze crusts. In these regions in particular, avalanches can release the entire snowpack.

In the morning, snow began to fall over a wide area, even down to low altitudes. It remained fairly sunny only in the far south. Fresh snow: In the period to Monday afternoon: - Glarus Alps to Alpstein, northern Grisons: 10 to 20 cm - Jura, other regions north of a line between the Rhone and Rhine, central Grisons: 5 to 10 cm - Elsewhere: a few centimetres, remaining dry in the far south Temperature: At midday at 2000 m: between -7 °C in the north and 0 °C in the south, falling further in the afternoon Wind: Mostly strong, occasionally storm force, from the west to northwest On Monday night, heavy snow will fall in the north and Grisons. Snow will fall in the other regions as well; only the far south will remain dry. The snowfall will ease temporarily during the day, before becoming heavier again towards the evening. The snowfall level will be at low altitudes. Fresh snow: From Monday evening until Tuesday evening: - Northern Alpine ridge from the Finsteraarhorn into the Urn Alps: 50 to 70 cm - Other regions on the northern Alpine ridge from Wildstrubel to Liechtenstein, rest of the Gotthard region, northern Grisons and Lower Engadine north of the Inn: 30 to 50 cm - Rest of the northern flank of the Alps, main Alpine ridge in Lower Valais, remaining parts of both central Grisons and Engadine: 15 to 30 cm - Elsewhere: up to 15 cm over a wide area, but only a little snow, or none at all, in central and southern Ticino Temperature: At midday at 2000 m: between -10 °C in the north and -4 °C in the south Wind: - At 2000 m in the north, strong from the west - At elevated altitudes and generally in the south, strong to storm force from the northwest to north

Wednesday: On Wednesday a further 50 to 80 cm of snow will fall from the Bernese Oberland to northern Grisons. 30 to 50 cm of snow will fall over a wide area in the other regions as well. Just a little snow will fall only on the southern flank of the Alps. The snowfall level will rise to approximately 1200 m in the north; it will remain at a lower altitude in the Alpine valleys. The avalanche danger will be high (level 4) over a wide area. On the southern flank of the Alps the avalanche danger will increase only a little. Thursday: On Wednesday night the snowfall will cease. During the day it will be fairly sunny and much milder. The zero degree level will rise to 2500 m in the east and south, and to 2800 m in the west. The avalanche danger will decrease. As a consequence of solar radiation and warming, however, natural slab avalanches can still occur, including large ones. On very steep sunny slopes, numerous loose snow avalanches originating in the fresh snow are to be expected.