A 15-metre stretch of the road to the Consolació sanctuary in Santanyi subsided into a quarry yesterday.
No traffic was passing at the time, although normally the road is used by hundreds of cars and coaches.
The landslide was discovered at around 7.30am, and has been blamed on the rain.
The road will remain closed to traffic for various days as reconstruction is complicated because of the danger of further landslides and the difficult access. An alternative access to the sanctuary will be provided.
The Santanyi council will open an investigation into the causes, but initially it is believed to be due to the action of the rain aggravated by activities in the quarry.
The rain coupled with high winds and rough seas has also caused the cancellation of various fast ferry services in the Balearics.
The company Balearia cancelled services between Majorca, Ibiza and Denia (Alicante) and the fast ferry between Ibiza and Barcelona.
The heaviest rain yesterday fell in the port of Pollensa, where 26.6 litres per square metre were registered. Rainfall at Lluc was 17 litres but it did not exceed ten litres per square metres in other parts of the island.
An improvement is expected today, with the sky clearing in the afternoon. Temperatures will start to go up, according to the met office.