San Francisco, March 9 : More than 17.5 million people across central and Northern California, including the San Francisco Bay area and state capital Sacramento, were under flood watches ahead of a storm set to lash the region on Thursday with dangerous amounts of rain in most of the places that currently have existing layers of heavy snow. "A storm arriving on 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," CNN quoted the Weather Prediction Center as saying in its latest forecast. "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," the center added. Officials in Monterey county have advised residents and businesses, especially in the Big Sur area, to stock up on essentials that would suffice for at least two weeks. The Big Sur area, roughly 150 miles south of San Francisco, is one of central California's renowned tourist attractions with picturesque rugged cliffs, mountains and hidden beaches along the Pacific Coast Highway. The county has also made sandbags available for residents to protect their property. Meanwhile in Marin county, Fire Department chief Jason Weber said they will have staff prepared for rescues in anticipation of possible flooding, county Fire Chief Jason Weber said. "Our reservoirs are all full from storms earlier this year. With reservoirs full, we expect our creeks will rise more rapidly with most of the rain becoming runoff," Weber told CNN. This week's severe weather threat comes as much of California has been hit with several back-to-back rounds of heavy snow that made roads impassable for days and knocked out power for thousands of residents as temperatures dropped. Previous severe weather claimed the life of one person in the San Bernardino Mountains area. /IANS