A storm packing powerful winds, rain and snow is expected to reach the Sacramento region starting late Wednesday night.
There are weather watches, warnings and advisories from the valleys to the mountains of Northern California.
Caltrans and the California Highway Patrol are among the agencies in an "all hands on deck" mode for the storm.
Chad Hertzell with the North Sacramento office of the California Highway Patrol said officers are out in "full force" on roads and highways.
"Making sure that the roadways are clear," said Hertzell. "We'll be working in conjunction with Caltrans. Also we'll be utilizing our freeway service patrol. If anybody gets stalled out during commute hours, we're going to make sure that they're towed out of the roadway."
The heavy rain is forecast to cause urban and small stream flooding.
Kris Kuhl, Caltrans Acting Deputy District 3 Director, said crews have been working the past two days to stem potential flooding problems.
"Clearing out the litter and debris from around our drainage inlets, filling potholes, checking culverts, and checking our pumps," said Kuhl.
Kuhl said crews in the Sacramento district will be working in 12 hour shifts from the Sacramento Valley to the Sierra.
"Equipment and materials are in place in the mountains and valley," he said.
Hurricane Force Winds Expected; Biggest Storm Since 2008
Michelle Mead, Warning Coordinator Meteorologist with the National Weather Service in Sacramento, said the storm will be the biggest to hit Northern California since 2008.
"We did have a lot of flooding and rain with that 2008 storm, we also had some high winds and some people were without power for a couple of days," said Mead. "This storm is comparable, but the winds look a little bit stronger and it also looks like the wind event will be a little bit longer."
She said the winds will begin to blow through the Sacramento region late Wednesday night, early Thursday morning.
Mead said wind gusts of 55 to 65 mph are forecast for the Sacramento Valley.
"So, to put that [wind gusts] in perspective, a Category 1 hurricane is 75 miles an hour, so we're pretty close to that," said Mead.
For the Sierra Nevada, she said a blizzard warning includes winds 25 to 50 miles an hour, with gusts to 75 mph or higher starting Wednesday night and continuing Thursday.
The National Weather Service has issued a blizzard warning for the western slope of the northern Sierra. Locations include Donner Pass, Echo Summit and Carson Pass. The forecast warned that hazardous whiteout conditions are possible and passes may close for several hours.
"Winds will increase tonight in the overnight hours," said Mead. "We'll see light rain showers moving into the Sacramento area, but the heaviest rain is expected Thursday during the day, shortly after the morning rush hour, but continuing through the evening rush hour."
She said last week's storm has saturated the ground, so, with 2-to-5 inches of rain forecast for the Sacramento Valley, Mead said flooding will be a problem.
"This much rain in a fairly short time will surely cause impacts especially to the afternoon and evening commute in the Sacramento Metro area," she said. "Urban and small stream flooding is likely. We are also watching portions of the Upper Sacramento River for flooding."
For commuters in the Valley or Sierra, travel is expected to be hazardous.
Mead said snow levels will start around pass levels and lower Thursday afternoon and continue to lower to around 4500 feet by Friday morning. The heaviest snow is expected to fall above 6000 feet, with about 1 to 3 feet expected.
Mead said the storm won't be a drought-buster for California.
"It's definitely a welcome sight, but remember we've got three years of dry to get over," said Mead. "So, a couple of storms looks awesome right now, but we've still got a long way to go."