The mudslide blocked the highway eight kilometres west of the junction with Highway 5 at around 12:30 p.m. PT.
RCMP Const. Lesley Smith said witnesses report the mudslide is about 15 metres wide and about half a metre deep over the highway.
"And it also appears that debris is still flowing, indicating the slide could get worse. There's no reports of any vehicles being trapped or any injuries, but the area is still extremely dangerous and unpredictable," she said.
Smith said the RCMP and the Ministry of Highways are at the scene assessing the situation.
DriveBC reports that a geotechnical assessment is being performed, and has not given an estimate of when the highway could be re-opened.