A section of the A9 autoroute in Valais has been closed to trucks and a lane closed for cars after part of the road collapsed.
A hole over a meter across opened up between Sierre and Sion - and police admit they have no idea why.
On worries heavy vehicles may cause more problems, any over 3.5 tonnes have to take a detour.
Engineers are now trying to figure out the reason for the collapse.
Heat to stay for now
Growing anger over World Cup red card
Fire damages trees in the Jardin Anglais
Cows sweltering in the heat
Lake Geneva nudists fight for their lake section
Holiday makers seek more than the sun
