YREKA, Calif.—Officials say Interstate 5 in far Northern California is closed after a crash involving about 60 vehicles.

California Department of Forestry and Fire Protection spokeswoman Julie Hutchinson says a number of people suffered minor to moderate injuries in a series of crashes that started around 6:30 p.m. Tuesday and stretched for nearly a mile along the northbound side of the freeway.

Hutchinson said she did not know the exact number of people injured, but said the southbound side of the interstate was closed so emergency vehicles could make their way to the scene.

It's not known what caused the pileup, or when the freeway would be open again, but Hutchinson says stretches of the roadway were icy. The National Weather Service has issued a winter weather advisory for the area.

The crashes took place near Yreka, just south of the Oregon border, or about 250 miles north of Sacramento.