RCMP Const. Leslie Smith says the slide occurred at about noon on Friday, when it was about 15 metres deep with debris flowing through it.
Smith said the area is extremely dangerous and unpredictable and motorists travelling east of Prince George should stay away from the area.
Police are on the scene, along with a Ministry of Highways geotechnician who s assessing the land.
It's not known when Highway 16 will be opened.
Drivers travelling west from Kamloops are advised to take an alternate route on Highway 97.
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