Al Richmond of the Cariboo Regional District says the "debris flow" on Thursday also isolated about 15 other homes near the community of Likely, which is about half way between Kamloops and Prince George.
The regional district says in a news release the flow is about two to three metres deep and 100 metres long, and the family had reportedly taken refuge in a boat on the lake.
Richmond says the flow of debris is still occurring, the area is not stable and an RCMP helicopter is flying a geotechnical specialist from the Ministry of Transportation over the scene.
He says the family has been spotted on the lake and is expected to spend the night with friends.
The Ministry of Forests defines debris flow as a rapid down-slope flow of debris that can include soil, weathered rock, mud, boulders and vegetative material.
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