It’s a long shot, but in the late 80s a levee broker at the river near the I-5 south of Sacramento and 5 was closed for a week or so.
If it keeps raining just check the how conditions on line when you are about to leave. I-5 would be my choice all the way to LA. 99 is further from the River and you can pick it up about Yuba City, but closer to the dam there IIRC.
Thanks, I’ll pass that along.