A potent atmospheric river, a weather phenomenon characterized by a narrow corridor of concentrated moisture, has left a trail of destruction across the U.S. state of California, causing at least seven deaths and shattering historical rainfall records. The storm system, which began moving through the state last week, triggered severe flooding, dangerous sea conditions, and warnings of potential mudslides in areas previously weakened by wildfires.

The series of tragedies began on Friday, November 14, 2025, when a seven-year-old girl was swept into the Pacific Ocean by waves estimated to be up to 20 feet high at a state beach. Her 39-year-old father, Yuji Hu of Calgary, Alberta, died attempting to rescue her, according to officials.

In a separate incident in Northern California's Sutter County, Arnold Jee, 71, was killed on Friday afternoon after his vehicle was carried away by rushing water while he attempted to cross a flooded bridge over Pleasant Grove Creek. The California Highway Patrol reported that signage was in place indicating the road was flooded.

Further south, off the coast of San Diego, a wooden boat suspected of smuggling migrants from Mexico capsized in the turbulent seas late Friday night. The U.S. Coast Guard confirmed that the incident resulted in at least four fatalities and four hospitalizations. Federal authorities have since charged a man, believed to be the boat's captain, with bringing people into the country illegally, according to court documents filed on Monday, November 17.

Record Rainfall and Ongoing Risks

The storm, a long plume of tropical moisture originating over the Pacific, first made landfall in the San Francisco Bay Area on Wednesday, November 12, before moving south and inundating Southern California on Friday and Saturday. Downtown Los Angeles experienced its wettest November in 40 years, breaking a record set in 1985. On Saturday, November 15, alone, the area received 1.65 inches of rain, a record for that date, according to the National Weather Service.

As of Monday, November 17, authorities continued to warn of lingering threats. The National Weather Service issued advisories for potential mudslides and rockslides in Los Angeles County, particularly in areas with burn scars from recent wildfires. "Due to the abundant rainfall the past couple of days, it will not take as much rainfall to cause additional flooding/rockslide conditions," the agency stated in an update on Sunday.

Global Context: Climate Change and Extreme Weather

While this storm has no direct impact on Kenya or the East Africa region, it serves as a critical case study in the increasing frequency and intensity of extreme weather events globally, a trend widely attributed by scientists to climate change. Atmospheric rivers are a natural part of the Earth's climate system, acting as vital conveyors of water vapor from the tropics toward the poles. However, scientific research indicates that rising global temperatures are amplifying their effects.

A NASA-led study projects that by the end of this century, atmospheric rivers will become significantly longer and wider, leading to more frequent and intense storm conditions. Studies suggest these phenomena could become 25 percent wider and longer, transporting substantially more moisture. This intensification increases the risk of megafloods and poses a significant challenge to infrastructure and water management systems worldwide, a concern relevant to all nations preparing for the impacts of a changing climate. The events in California underscore the urgent, global need for robust climate adaptation and mitigation strategies.