Massive waves and coastal flooding are wreaking havoc for a third day in many of California's coastal communities, where extreme conditions have forced water rescues, washed away cars and injured a handful of enthralled onlookers. The unusually large surf — often towering over 20 feet — has prompted beach closures along the California coast and sent damaging deluges of water into several beachside streets, homes and businesses. In hard-hit Ventura County, waves have surged over seawalls and carried parked cars down the street and into significant intersections, blocking first responders' paths, fire captain Brian McGrath told CNN affiliate TNLA. Flooding in a local hotel also caused damage in all of its ground-floor rooms, he said. High water and dangerous rip currents have been besieging much of the West coast from southern California to Oregon since Thursday, caused by a series of powerful storms that have been making their way ashore from the Pacific Ocean. Though hazards will lessen for Northern Californians on Saturday, coastal areas of central and Southern California will keep being battered by extreme surf, which could reach about 25 feet in impacted areas. Some waves slamming into California's Bay Area may peak at 40 feet — about the size of a telephone pole — and others are expected to hit 28 to 33 feet. Southern Oregon's coast is also set to be buffeted with strong surf and high winds early Saturday. High surf warnings are in effect in the region through Saturday morning as waves between 20 and 25 feet are expected. Curious onlookers and excited surfers have been enthralled by the spectacular surf, but local officials are urging people to stay out of the water and away from the beaches due to potentially life-threatening conditions. "Beaches, piers, vulnerable harbors should NOT be considered safe," the National Weather Service in Los Angeles said. Ventura County officials have closed all beaches through New Years Eve due to the 15- to 20-foot waves set to slam into the coast through Saturday evening. The county, along with Hermosa, Manhattan and Palos Verdes beaches, face the most extreme surf on Saturday and are at risk for significant coastal flooding. "We know the waves look impressive and we understand the drive to want to come here," McGrath told TNLA Friday. "But we're asking people to stay away and stay out of the area for their safety and for ours." Ventura first responders rescued about 10 people on Friday "who thought they were able to navigate that high surf," the fire captain said. Two beachgoers also helped pull a struggling lifeguard out of the water as the lifeguard was trying to get back to shore after rescuing a person near the pier, firefighter Andy VanSciver told CNN. During the first round of severe surf on Thursday, nearly 20 people were swept away by a wave that slammed into a beach barrier lined with onlookers in Ventura Beach's Pierpont area, officials said. Eight injured people were taken to the hospital. "It was terrifying and apocalyptic," said Colin Hoag, who captured a video of people scrambling to escape as the towering wave crashed over the barrier. Quickly moving seawater swept some people off their feet and pummeled cars as drivers tried to speed away. "People were yelling and screaming. I ran as fast as I could," Hoag said. One of the storms fueling the waves will also bring rain and wind to California through Saturday. By Saturday morning, the rain will shift inland and across Southern California before weakening over the Rocky Mountains on Sunday. Further inland, a wintry mix will fall on areas of central and eastern California. More than a foot of snow is possible over high elevation crests and peaks and between 6 to 12 inches is expected in lower elevation mountain areas. — CNN