An RCMP dive team is searching for signs of an 18-year-old who disappeared below the surface while swimming in Chilliwack Lake.

Police and search and rescue crews were called to the area Tuesday afternoon after a boating incident in the southeast end of the lake.

A group of four had been out boating and pulled ashore. When the boat started to drift away, the 18-year-old swam out to bring it back. He disappeared beneath the surface of the lake and never came back up, officials said.

The water is estimated to be about 30 metres deep in the area he was last spotted.

Mounties and Chilliwack SAR searched the shoreline for signs of the swimmer, but said Wednesday the land search had been scaled back.

The RCMP's underwater recovery team has been brought in to search the lake.

With files from CTV Vancouver's Ben Miljure