Northbound lanes of Interstate 5 in far Northern California have reopened after a series of traffic collisions involving about 60 vehicles shut down the roadway.

The California Highway Patrol says the highway reopened at 5 a.m. Wednesday, about 12 hours after authorities received a report of a crash there north of Yreka near the Oregon border.

Additional crashes were still occurring when the first officer responded. The CHP says eight people were transported to hospitals. Six of them were treated and released. Two others were admitted for serious injuries.

More than two dozen vehicles had to be towed from the roadway.

It's not known what caused the pileup, although the CHP says the roadway was icy. The National Weather Service has issued a winter weather advisory for the area.