Unseasonably cold weather prompted many Swiss residents to head south toward the canton of Ticino and Italy causing major tailbacks through the 17-kilometre Gotthard road tunnel, the SDA news agency reported.
Delays of more than an hour and 15 minutes were reported on Monday afternoon between Faido and Airolo on the A2 motorway, with the traffic piled up for seven kilometres, SDA said.
The tailbacks were expected to lengthen through the evening.
Traffic was reduced to a virtual standstill for eight kilometres on the A13 highway between Pian San Giacomo and the San Bernadino tunnel in the canton of Graubünden, SDA said.
The 6.6-kilometre tunnel connects eastern Switzerland with the canton of Ticino.
Traffic was reported heavy on the A1 motorway between Dietikon and the Gubrist tunnel in the canton of Zurich, travelling in the direction of Saint Gallen.
And Zurich’s western bypass was also overloaded, SDA said.
Strong winds and freezing overnight temperatures marred the long weekend in much of Switzerland with snow in the Alps.
Orchards in the canton of Valais, where fruit trees have just begun to blossom, were hit by ice, the ATS news agency reported.
With school holidays under way — extending in some cases until May 10th — heavy traffic is expected particularly on the north-south axis roads that link northern Switzerland to Italy.
Holdups are expected through the Gotthard tunnel every day until Thursday, ATS said.
Part of the reason for the heavy traffic is German and Dutch holidaymakers passing through Switzerland on their way to seek warmer weather in Italy.
Meanwhile, Touring Club Schweiz (TCS) reported that 15 roads through Swiss mountain passes that close for the winter have yet to reopen.
Cantonal roads between Feschel and Erschmatt and Fully and Chiboz in the canton of Valais remained closed due to avalanche risks, TCS said.
A landslide closed another cantonal road in Valais between Vercorin and Pinsec.
Avalanche concerns, meanwhile, led to delays of local trains in Graubünden.