CNN  — 

Officials in California are imploring residents to prepare for a powerful storm set to lash the region with torrential rain later this week as the state continues to recover from colossal amounts of snow that trapped mountain communities.

Previous severe weather was responsible for the death of one person in the San Bernardino Mountains area. The San Bernardino County Sheriff’s Office said the person died in a traffic accident. Other deaths since February 25 don’t appear to be weather-related but investigations are ongoing, spokesperson Mara Rodriguez said.

About 17.5 million people across central and Northern California – including the San Francisco Bay area and Sacramento – and parts of Nevada were under flood watches Wednesday ahead of a storm set to drench the region Thursday with dangerous amounts of rain in most of the places that currently have existing layers of heavy snow from previous brutal storms.

“A storm arriving Thursday will bring a threat of flooding from a combination of heavy rain and snowmelt to lower elevations and foothills in California, especially below 5000 feet,” the Weather Prediction Center said. “And heavy, wet snow at higher elevations will lead to difficult travel and impacts from snow load.

“Creeks and streams in the foothills of the Sierra Nevada will be most vulnerable to flooding from rain and snowmelt.”

In response to the ominous forecast, officials in Marin and Monterey counties in California have begun preparations ahead of the looming storm, which is expected to strike the area as a strong