Daily precipitation and daily mean temperature
Between 10 and 12 February 1990, 25 to 70 mm of precipitation was measured in the Jura mountains, in the Vaud Alps and on the eastern Alpine north slope. With the passage of a cold front on 11 February, the snowline was lowered to around 700m altitude, and on 11 and 12 February the precipitation fell as snow in those regions, while it fell as rain in lower elevated areas, for e.g. at the foot of the Jura or at the foot of the Alpstein.
During the day of 13 February, the precipitation increased considerably, with a daily sum of 35 to 110 mm measured in the regions mentioned above. With the arrival of warm and moist air from the west during the night of 13 to 14 February, the temperatures increased (see figure below), the snow line rose to an altitude of approximatively 1700m and the snowfall turned into intense rainfall in the Jura mountains as well as in the parts of the Vaud Alps and the eastern Alpine north slope located below that altitude.