Drivers going over the river and through the woods may need to pack their patience as interstate holiday jams from Roseburg to Redding, Calif., are likely, according to the Oregon and California departments of transportation.

Drivers going over the river and through the woods may need to pack their patience as interstate holiday jams from Roseburg to Redding, Calif., are likely, according to the Oregon and California departments of transportation.

A mix of heavy holiday traffic, snowstorms on the Siskiyou Pass and bridge repair work is causing major congestion on I-5 in Southern Oregon. ODOT reported backups extending five to eight miles earlier this week. Bridge repair projects underway near Grants Pass and Myrtle Creek reduce I-5 to a single lane in each direction.

Combined with the first major snowstorms on the Siskiyou Pass and increased traffic volumes for the holidays, delays along I-5 are likely.

"Congestion occurs when there's a break in the storm," said ODOT District Manager John Vial in a news release. "Trucks tend to bunch up and wait for a clearing. Anywhere a lot of trucks and heavy holiday traffic meet will cause congestion."

Vial encourages local motorists to use alternate routes to avoid congestion and delays.

The California Department of Transportation District 2 advises motorists to prepare for delays of up to an hour on I-5 at the Pit River Bridge. Construction continues and traffic remains reduced to one lane in each direction.