Caltrans made the announcement on Twitter at approximately 9:15 p.m. Sunday and warned drivers to be patient and drive slow.
The agency had already deployed snow plow crews to the area as a precaution, and those crews were expected to stay there overnight.
By Monday morning, the 5 Freeway remained open and drivers were no longer being escorted, but weather conditions were still rough.
The snow sometimes fell sideways because of the wind.
Drivers traveling northbound on the freeway were still encourage to take it slow.