A powerful double whammy of an atmospheric river and bomb cyclone continues to drench California on Thursday, dropping several inches of rain on a region that has struggled to wring out from an onslaught of winter storms and creating a widespread risk of flooding, mudslides and power outages in what some forecasters are suggesting will become one of the most impactful storms to strike the state in years.
Fox says the storm has been blamed for at least two deaths in the San Francisco Bay Area, with a 2-year-old child killed Wednesday inside a home that was hit by a falling redwood tree in the rural Sonoma County town of Occidental, according to local firefighters.
And in Fairfield, a 19-year-old woman was killed when her car hydroplaned on a partially flooded road and slammed into a utility pole, according to Fairfield Police.
California Gov. Gavin Newsom's office declared a state of emergency Wednesday and said their storm response offices are at their highest emergency level.
The storm underwent rapid development off the California coast over the past 36 hours, becoming what meteorologists refer to as a bomb cyclone. As the storm intensified, it tapped into abundant tropical moisture available in the Pacific Ocean, creating a reasonably strong "atmospheric river" carrying copious amounts of moisture from Hawaii to California.
This specific type of atmospheric river, known as the "Pineapple Express" in a nod to the storm's fuel source due to its Hawaiian origins, is set to bring significant moisture to California. Think of this as a narrow pipeline of moisture that originates in the tropics.
Of particular concern are the potential for debris and mudflows where heavy rain falls in areas burned by major wildfires in the state over the past few years.
Some areas along the Northern and Central California coast could see 5 to 8 inches of rain, while farther inland, rainfall totals in the mountains and their foothills could approach 8 to 12 inches in some spots.
The San Francisco Bay Area, which saw its second-wettest day on New Year's Eve, could see an additional 2 to 5 inches of rain with locally higher amounts.
Even the Los Angeles area could have 2 to 4 inches of rain – with 4 to 8 inches of rain possible in the Southern California mountains – by the time the storm system moves through.
According to the AccuWeather, a bomb cyclone, or bombogenesis is a storm (low pressure area) that undergoes rapid strengthening. The vast majority of such storms occur over the ocean. The storm can be tropical or non-tropical in nature.
The bomb cyclone currently over the Pacific that’s striking California is expected to bring two to four includes to Southern California valleys between Wednesday and Thursday and even great amounts to mountains and foothill areas, the National Weather Service reports.
Images courtesy of National Weather Service and National Oceanic and Atmospheric Administration