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."
Do you have pictures - still or moving - of this incident? Send them to the BBC news website. Click hereto send an email.
If you want to send your picture from your mobile phone, email them to firstname.lastname@example.org. You can send them from any network or phone. Please send the large full size images (usually 640x480 pixels) taken by the mobiles otherwise they are too small to publish.
Please ensure when filming or photographing an incident that you make your safety and the safety of others a priority.
In contributing to BBC News Online you agree to grant us a royalty-free, non-exclusive licence to publish and otherwise use the material in any way that we want, and in any media. (See the Terms and Conditions for the full terms of our rights.)
It's important to note, however, that you still own the copyright to everything you contribute to BBC News Online. This means you are perfectly free to take what you have produced and re-publish it somewhere else. Please note that if your image is accepted, we will publish your name alongside it on the BBC News website. The BBC cannot guarantee that all pictures will be published and we reserve the right to edit your comments.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.