CALIFORNIA - As the rain hits the windows of the AndNowUKnow headquarters here in Sacramento, California, a recent update from AccuWeather shows torrential rain across much of the state as an atmospheric river begins.

“The biggest storm of the winter, packing a firehose of rain across much of California, will trigger flooding, mudslides, and road closures that may put lives and property at risk into the end of the week. Feet of snow will also pile up over the high country of the Sierra Nevada,” the source’s experts warned.

The quick-moving atmospheric river will direct a period of torrential rain along the shoreline, the Coast Ranges, and the lower west-facing elevations of the Sierra Nevada, into Friday. With much of the storm's rain likely to fall in 12 hours or less, meteorologists have noted the potential for disastrous flash flooding, mudslides, and hillside collapses in steep terrain areas.

"Making matters much worse will be the burn scars of the recent wildfires that swept through South California," AccuWeather Senior Director of Forecasting Operations Dan DePodwin explained. "There is little to hold back the water and mudflows as the onset of storms demonstrated in late January. Some of the runoff can be toxic in some locations as it washes ash and other debris into streams and then reaches the beaches.”

Roughly 2-4 feet of snow is expected to fall on the Sierra Nevada above 6,000 feet, AccuWeather Chief On-Air Meteorologist Bernie Rayno reported. "Local amounts up to 6 feet can occur over some of the ridges and peaks in the California mountain range," he said.

This could lead to temporary problems such as road closures—including along Interstate 80 and Donner Pass, California. Along with the likelihood of flooding, mudslides, and feet of snow in the Sierra Nevada, the atmosphere may get wild enough to trigger thunderstorms on Thursday, the source noted.

ANUK will continue to keep a tab on weather impacts across the Golden State, so stay tuned.