Southern California beachgoers are being warned to stay out of the water this week when a massive winter storm brings rain, wind and waves as high as 25 feet to the coastline.
The National Weather Service has issued a high-surf advisory from the Central Coast to Ventura County lasting from Thursday to Saturday as a Pineapple Express weather system as wide as 400 miles shoots a blast of cold air, rain and wind across the state.
"Waves will over-top jetties and sea walls at times," the National Weather Service said in its surf advisory Wednesday. "Waves will potentially wash into low-lying beach areas or parking lots at times."
This winter storm features an "atmospheric river," which can be up to 400 miles wide and can cause major flooding when stalled over an area, according to the weather service.
Such rivers are relatively narrow regions in the atmosphere responsible for transporting water vapor horizontally outside the tropics, the weather service says. On the West Coast, the weather event is also known as the Pineapple Express.
Those brave enough to venture out into the water Wednesday should be getting a preview of what's in store into the weekend.
Waves from 10 to 15 feet are already showing up along the Ventura County coastline with some sets as high as 18 feet, the weather service said. The sets will continue to grow in the coming days and could peak at 25 feet.
The advisory does not apply to Los Angeles County. However, while Angelenos may not bear the brunt of the storm's surge, they're still expected to get slammed with cold winds and inches of rain.
Isolated foothill communities could experience wind gusts as strong as 70 mph, the weather service said.
But forecasters are quick to note that the biggest issues will hit Bay Area residents.
"Bottom line … now is the time to prepare before the storm on Thursday," forecasters for the weather service's Bay Area region said in a statement. "Preparations should be made ASAP."
Mountains lining the coast from Sonoma to Santa Cruz could get as much as 8 inches of rain by Thursday morning, said meteorologist Charles Bell. Some wind gusts could be as powerful as 70 mph. It's the biggest storm the region has seen in as long as 10 years, he said.
In Northern California, people living above 6,000 feet in areas including Lassen National Park and Donner Pass could be hit by a blizzard, forecasters say. A winter storm warning will be in effect from 10 p.m. Wednesday until 1 p.m. Friday. The weather service said residents could experience whiteout conditions, which could lead to roadway closures lasting several hours. Ten to 20 inches of snow could accumulate in those communities.
The northern Sierra crest could get 2 to 3 feet of snow, with the heaviest snowfall Thursday night. The strongest winds there are expected Wednesday night and Thursday with 20 to 25 mph winds and gusts more than twice that. Snow is expected to fall as low as 4,500 feet on Thursday night and Friday morning.