More than 26 million people in California, which has already been devastated by a number of disastrous storms, are under flood watches.
Through the weekend, the majority of the state is expected to get precipitation from two Pacific storm systems. In many areas that have already seen flooding recently, the broad inundation is raising those concerns.
The impact of atmospheric rivers has practically reduced California's "extreme" drought classification.
The National Weather Service stated in a bulletin on Saturday that the systems are anticipated to produce "heavy lower elevation rain, considerable mountain snow, and severe winds."
The Sacramento County Office of Emergency Services issued an evacuation notice for many regions Saturday afternoon due to a flood hazard as one of the effects so far. Authorities in Placer County said that Saturday's road closures were also caused by erosion from runoff and falling boulders.
The first system is anticipated to come inland Saturday night and drop a lot of rain on California. The National Weather Service cautioned that 2 to 3 inches of rain might fall near the coast and cause "localised cases of urban and small stream flooding as well as mudslides."
On Sunday, there may be less rain, the agency warned, "with another ramp-up late Sunday into early Monday ahead of a second system."
Additionally, wind advisories are in effect for areas of the coast and Central Valley for persistent winds of 20 to 30 mph and 50 mph gusts.
Throughout the weekend, snow will also continue to fall in the Sierra Nevada Mountains, with 3 to 6 feet of accumulation expected through Monday.
At noon on Saturday, the Central Sierra Snow Lab at UC Berkeley reported a snowpack that was about 10 feet deep and that had received more than 21 inches of snow in the previous 24 hours. By Monday morning, another 2 to 3 feet of snow are predicted to have fallen.
A nearly continual barrage of rain and snow has pummelling California. According to state officials, a violent storm system earlier this week caused at least 17 fatalities.
The upcoming week on the West Coast was expected to see a "relentless parade of atmospheric rivers," according to the National Weather Service.
Gov. Gavin Newsom of California encouraged citizens to "stay careful" as more hazardous weather was predicted for this weekend.
At a news conference on Friday, he stated, "I realise how worn out you all are." We'll get through this, I just hope you keep a bit more watch throughout the course of the following weekend.
According to the governor, the state is likely to see storms through January 18.
Daniel Amarante of ABC News contributed to this story.
