Temperatures dipped to below -20 in several locations in Switzerland on the night of Friday to Saturday, the coldest of the winter so far.
A number of locations in the north-east recorded their lowest February temperatures for 30 years.
The cold weather disrupted some rail services because points froze. The line between Lausanne and Geneva airport was particularly badly hit, with only two tracks usable. The Swiss Federal Railways said trains were experiencing delays of about half an hour.
Although about 60 per cent of all points are equipped with a heating system to prevent them icing over, this does not always work when it is colder than -15, the company said.
The motoring organisation TCS said it had received about 8,000 calls by Saturday afternoon – a record. On an average February day it handles about 1,400. Most calls were to do with flat batteries and frozen doors, contacts and brakes.
According to the SF Meteo weather service, the very lowest overnight temperature, -34, was recorded on the Glattalp in the central canton of Schwyz.
The village of La Brévine, in the Jura in western Switzerland, reputed to be the coldest place in Switzerland, recorded a temperature of -23.9. However, this is well above the Swiss record it set in 1987 of -41.8.
Even in the plateau area, temperatures varied between about -15 and -20. At Zurich airport it fell just below -20 in the coldest part of the night.
Major cities were not spared either. Basel recorded a temperature of -18.4, and Bern -16.1.
Temperatures remained below zero throughout the country on Saturday. The warmest place was Ascona, near the Italian border, at -2.
Another freezing night is forecast.
swissinfo.ch and agencies