The evacuation of residents at several farms in Renfrewshire has begun after heavy weekend rain put huge strain on the walls of a reservoir.
Environment chiefs issued a warning that the integrity of the dam, near Lochwinnoch, had been affected.
Concerns were raised that a burst would cause water to sweep down the nearby Maich Burn and flood homes.
Engineers have been controlling the release of excess water in a bid to take pressure off the structure.
The A760 Lochwinnoch to Kilbirnie road was closed as a precaution and drivers and pedestrians were warned to stay away from the area.
Diarmid McArthur, who lives two fields away from the Maich Burn, near Ladyland Castle, moved into a nearby guest house with his wife and two daughters after the police came to his door.
A breach of the dam could "endanger life", police have said
He told BBC Scotland: "It's really a surreal situation. One minute you're playing with your daughters - we'd cut the grass, we'd been weeding - and the next minute they're saying you need to leave your house.
"It's not the kind of thing you normally expect."
The Scottish Environment Protection Agency said there was a risk of the sudden release of water stored behind the dam.
It added: "Should there be a significant release of water, there will be a rapid increase in the volume, depth and velocity of water in the Maich Water channel.
"There is therefore a risk of flooding and erosion of the channel."
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