The very deep layers of fresh fallen snow and freshly generated snowdrifts which were unleashed in numerous places on Tuesday
and on Wednesday lie deposited on west-facing, north-facing and east-facing slopes atop an unfavourable, expansively metamorphosed
(faceted) weak layer.
More deeply embedded inside the snowpack in the Jura region, on the northern flank of the Alps and in the western part of
the Lower Valais are deep rain crusts which formed in the final week of the old year and extend up to high altitudes in some
places. These rain crusts stabilise the lower part of the snow cover below approximately 2700 m in these regions, so that
avalanches can hardly ever fracture down to the more deeply embedded layers of the snowpack.
From the southern Valais over the northern Ticino as far as Grisons, on the other hand, the entire snowpack is often expansively
metamorphosed (faceted) and riddled with thin melt-freeze crusts. In these regions more than anywhere else, avalanches can
sweep along the entire snowpack.
As a result of the measurably higher temperatures and the daytime increase in solar radiation, naturally triggered avalanches
can be expected on sun-drenched slopes, in particular in the regions where snowfall has been heaviest. At intermediate altitudes
on very steep grass-covered slopes, gliding avalanches can be expected.