Police are investigating whether a woman is trapped inside a house after part of the property collapsed during heavy rainfall.
Devon and Cornwall Police say Susan Norman, who is in her 60s, has not been seen or heard of since 6pm on Thursday.
Her house in Looe, Cornwall, was hit by a landslide and floodwater on Thursday night.
The property, named "Veronica", is one of a number of detached homes along the road, overlooking a sheer drop to the picturesque Looe Valley branch line.
Sandplace Road, which runs along the entrance to the properties, has been closed to traffic for months after a landslide nearby just before Christmas.
More than a dozen people living in the street have been evacuated and accounted for.
Neighbours said they heard "windows popping" at the three-storey property under the pressure of a torrent of surface water which had been washed down the road behind the building, which is split into three flats.
Devon and Cornwall Police duty inspector Graham Claybourn said: "The property and adjoining properties were evacuated this morning (Friday), everybody was accounted for.
"However, one lady has not been accounted for. She lives in the ground flat. We're waiting for a geothermal engineer from the council to come down and assess the scene. There was some building work going on (in the area) at the time."
Police and fire crews are waiting for engineers to assess whether or not the building is safe enough for further searches. A springer spaniel sniffer dog, used by emergency services to detect the scent of humans, was sent to the edge of the property.