Northern California Facing Fresh Hit From 'Enormous' Cyclone

California is squaring up to an "enormous" cyclone that will push farther northwards up the West Coast than recent storms. It will come after a brief reprieve from the last weather event—the sixth since late December—which has caused widespread destruction and brought the confirmed death toll to 17.

The National Weather Service (NWS) said in a forecast on Wednesday that the storm, currently rotating "well off" the West Coast, would bring the next round of heavy precipitation, "targeting northern California."

"Unlike the recent atmospheric river events, this upcoming event is forecast to impact areas farther north from northern California and up the coast of the Pacific Northwest through the next few days," it added.

NWS meteorologists are anticipating several inches of rain over the coming days to impact north-western California.

"We're soaked, this place is soaked. And now, [a] more modest amount of precipitation could add equal or greater impact in terms of the conditions on the ground," Governor Gavin Newsom said while visiting storm-damaged businesses in Capitola, on the Santa Cruz coast, on Tuesday.

Counties in northern California are preparing for the weather front. On Tuesday evening, Shasta County warned residents not to drive through flooded roads and to avoid approaching power lines that had fallen over in the high winds.

"The Mt. Shasta region will continue to see the most snow impacts. Snow levels will become notably higher around Thursday and Friday," the Siskiyou County Office of Emergency Services said in a Facebook post on Tuesday. Areas of the county near the border with Oregon were among those under evacuation orders earlier in the week.

In Del Norte County—the northern-most coastal area of California—a flood preparation training session was cancelled on Sunday by the Office of Emergency Services due to the flooding.

Wednesday's cyclone will be the latest in a series of high-intensity storms to hammer California since New Year's Eve, which have left thousands of homes without power across the state and thousands of families evacuated due to flooding.

The West Coast has been battered by what the NWS described on Sunday as a "relentless parade" of atmospheric river storms, with between 400 and 600 percent of historic averages of rainfall falling during the winter storm period.

The high volumes of rainfall are due to the cyclones mixing with an atmospheric river—a channel of warm, moist air that flows toward California. As the colder Arctic air of the cyclone percolates with the warmer air from the subtropics, it creates a higher amount of precipitation.

As well as high floodwaters across California, the intense amount of rainfall has brought rock and mudslides—exacerbated by drought conditions—that have blocked roads and damaged property.

Christopher Kilburn, professor of geophysical hazards at University College London, U.K. told Newsweek: "If they're starting, then it's likely that there'll be others. It's difficult to imagine that all the slopes that could fail will fail on the first go, so if you're continuing to pour water into the rock through continuing storms, then there's likely to be further mud flows. It will be areas in the same vicinity but also adjacent to where they started."

In northern California, images posted on social media show a landslide in western Siskiyou County, with large boulders covering mountain roads. Another, taken by local radio station Kcre Kpod in Del Norte County, shows Highway 101 between Port Orford and Gold Beach washed away.