Northern California flooded after powerful storm brings drenching rain

Flash flood warnings were issued on Sunday in parts of northern California after a powerful storm brought drenching rain and heavy snowfall overnight, snarling traffic and closing highways as the state ushered in the new year.

Many roads were under water on Sunday. And in the high Sierra Nevada, snow accumulated and the National Weather Service in Sacramento warned about hazardous driving conditions and posted photos on Twitter showing traffic on snow-covered mountain passes, where vehicles were required to have chains or four-wheel drive.

The so-called atmospheric river storm was pulling in a long and wide plume of moisture from the Pacific Ocean on Friday and Saturday. Flooding and rock slides closed portions of roads across northern California. Precipitation was easing as the new year was rung in, but the threat of flooding remained.

The Sacramento region could receive a total of four to five inches of rain over the span of the week, Chandler-Cooley said.

The extreme weather came amid the longer-term picture of a historic mega-drought in the area and the wider region, punctuated by devastating wildfires over a prolonged season, that adds up to a climate disaster in the American west.

Meanwhile, almost 300 miles north-west of Sacramento, an earthquake, preliminarily reported at a magnitude of 5.4, hit the area near Rio Dell on Sunday, in Humboldt county.

No injuries were reported but the temblor came weeks after a 6.4 magnitude earthquake in the same region on December 20, which killed two people and caused widespread power outages.