Police in Coquitlam, B.C., say first responders are searching for a person who is unaccounted for after their home was washed away in a mudslide triggered by torrential rain across British Columbia鈥檚 south coast this weekend.

Coquitlam RCMP say officers responded to a report of the slide along Quarry Road on the east side of Pinecone Burke Provincial Park at about 12:30 p.m. Saturday.

They say the slide washed away one home and police were communicating with the family of the owner, who is unaccounted for.

The slide has rendered the road impassable, cutting off several other residents who have confirmed with emergency personnel that they are sheltering in place.

B.C.鈥檚 River Forecast Centre, meanwhile, has downgraded flood warnings for the Coquitlam River and waterways on southwestern Vancouver Island.

Lower-level flood watches now cover the southern half of Vancouver Island and the rest of the province鈥檚 south coast, including the Sunshine Coast, Metro Vancouver, the Sea to Sky corridor and the Lower Fraser River and its tributaries.

An update from the centre says additional rainfall was expected Sunday night as a 鈥渟econd and final pulse of moist air鈥� moves from the coast to the Interior.

The atmospheric river weather system that lashed B.C.鈥檚 south coast on the day of the provincial election sent daily rainfall records tumbling on Saturday.

Environment Canada figures show new daily rainfall records were set in Victoria, Squamish, Vancouver, West Vancouver, White Rock, Langley, Abbotsford, Chilliwack, Hope, Nakusp and the Agassiz and Pitt Meadows areas.

West Vancouver saw 134.6 millimetres of rain, smashing the record of 34.8 millimetres set in 1970, and images posted to social media in the city on Saturday showed a surge of brown floodwater flowing down a sloping street.

Since Friday, Environment Canada said West Vancouver has seen a total of 177 millimetres of rain, with 150 millimetres falling in the Vancouver harbour area.

Rrainfall warnings remain in effect for much of the south coast, with Environment Canada saying Metro Vancouver and parts of the Fraser Valley could see an additional 20 to 40 millimetres before the rain is expected to ease later Sunday.

The BC Hydro outage map shows several thousand customers without power across the Lower Mainland and the Sunshine Coast on Sunday afternoon, along with about 700 customers on Vancouver Island.

A rainfall warning also covers parts of the West Kootenay and Columbia regions, including a stretch of the Trans Canada Highway between Revelstoke and Golden.