CALGARY -- A rock slide has forced the closure of the Trans-Canada Highway in both directions east of Golden, B.C. on Sunday morning. It has since reopened to single lane, alternating traffic. 

According to the website Drive BC, the highway was closed about 6:30 a.m. MT between Golden Donald Upper Road and Ten Mile Hill Truck Stop Road.

A spokesperson with the B.C. Ministry of Transportation says about 3,000 cubic metres of debris came down, impacting the highway about four kilometres east of Golden.

"The area is in a freeze-thaw cycle and it was raining prior to the event," reads a statement.

"Geotechnical engineers are on site doing an assessment and clean up has commenced. We hope to have traffic moving again by late afternoon but this is dependent on the geotechnical assessment."

Motorists were advised to use Highway 95 and Highway 93 through Radium, B.C. as a detour during the closure.

The spokesperson said roughly 4,000 vehicles pass through that stretch of highway per day at this time of year. Golden is about 264 kilometres west of Calgary.