A large rock which fell from a cliff came crashing into the bedroom of a seafront flat.
The occupant of the first-floor flat, in Hastings, East Sussex, was not at home when two boulders weighing several tonnes tumbled into a building on Thursday.
One caused damage to the room, while the other landed on the flat roof of a ground floor shop in White Rock.
Hastings Borough Council said the tenant of the flat had been found alternative accommodation along with three people from another flat, and officials were arranging for the cliff to be surveyed.
Spokesman Kevin Boorman said letters had been delivered to about 35 other properties advising residents that their homes may not be safe, and that they should move out.
They will be put up by the council this weekend but must find their own accommodation from Monday.