A cold snap has brought winter conditions to altitudes above about 1,000 metres in Switzerland.
Between five and 15cm of snow fell on the northern slopes of the Alps and in the southern canton of Valais during the night of Friday to Saturday.
The traffic information centre Viasuisse said on Saturday that nine passes, including the Gotthard, had been closed to traffic.
In addition, several of the main passes leading into Italy were snow covered, and chains were made compulsory on the Bernina. However, access to the road tunnels and car trains was open.
Three people were killed and seven injured in canton Graubunden on Friday, when a bus skidded on a snowy road and hit an oncoming truck.
The Swiss meteorological service, MeteoSwiss, said it is not unusual for snow to fall at 1,000 metres at the beginning of October. But a thaw is expected to set in on Sunday.