California is preparing for a powerful atmospheric river storm, forecasted to impact large areas of the state with substantial rain and heavy snowfall in mountainous regions.

The National Weather Service (NWS) has issued winter storm warnings across much of northern California due to the anticipated gusty winds and significant snowfall, predicting 'difficult to impossible travel conditions.'

In southern California, a flood watch has been declared, effective through Thursday afternoon.

Authorities expect hazardous driving conditions and the likelihood of road flooding and debris flows, particularly in regions previously affected by wildfires.

As a precaution, various areas in Los Angeles have been placed under evacuation warnings and orders, with several roads, including portions of the Pacific Coast Highway, announced for closure.

In preparation for the approaching storm, the state’s office of emergency services has deployed over 400 workers statewide.

This includes swift-water rescue teams and urban search and rescue personnel.

Residents are encouraged to prepare for potential power outages and have emergency 'go-bags' ready.

Atmospheric rivers, which are long, narrow bands of moisture originating from the ocean, play a critical role in replenishing California's reservoirs and snowpack.

However, they have also been linked to some of the state’s most severe weather incidents, including a series of storms in 2023 that resulted in approximately 20 fatalities.

Recent studies indicate that these phenomena have been increasing in frequency and intensity over the past 45 years, correlating with climate change.

A comprehensive study published in the Journal of Climate highlights that the intensity of heavy rainfall and wind associated with atmospheric rivers in California and the broader western United States has escalated significantly.

Specifically, since 1980, the area affected by these storms has grown by 6% to 9%, with the frequency of such events increasing by 2% to 6%.

Additionally, the overall moisture content in these storms has slightly risen.

Researchers, including Lexi Henny, a leading atmospheric scientist, suggest that while the study does not directly attribute these changes to climate change, the data align with concerns regarding the future impact of global warming on atmospheric events.

Henny’s research emphasizes that while current changes are noteworthy, they are modest compared to what could be anticipated in a significantly warmer future.

Although atmospheric rivers can provide much-needed rain to combat drought conditions, they pose significant risks.

Historical precedents, such as the atmospheric river events in California last year, led to numerous mudslides and fatalities.

The impact of atmospheric rivers is not limited to California; similar weather patterns have been recorded across the United States and globally, although they may not always be classified as such.

Notably, a 2023 atmospheric river in New England produced a foot of rain and winds reaching 50 mph, while another event in 2020 led to nearly 99 inches of snow in Alaska.