The California Floods & What They Reveal About This Year’s Weather “Nightmares”

As the holiday season arrived, some California residents were met with what could quite literally be called a “nightmare before Christmas.” Torrential rain and sharp wind gusts barraged several Southern Californian counties, bringing intense flooding, mudslides and power outages, prompting Governor Gavin Newsom to declare a state of emergency. Though California is headed into a cool and dry week ahead, the effects will likely continue to linger. In total, the storm dropped six inches of rain in the Los Angeles area, downpoured upwards of eighteen inches in mountainous regions and claimed the lives of three people.

A combination of factors drove the rainfall. Typically, three conditions need to be met to produce powerful thunderstorms: atmospheric moisture, unstable atmospheric conditions and a source of “lift” to force air upward and drive thunderstorm development. In California’s case, the deluge was spurred primarily by the first condition, or more specifically, what some experts term an “atmospheric river.” Essentially, large plumes of moisture in the atmosphere were carried inland from the Pacific, which then rapidly rose, cooled, and fell as precipitation. These rivers, though invisible, can carry as much water as the Amazon. Thus, it is no surprise that the force of flooding was immense.

Yet, meteorologists conclude that it wasn’t just this phenomenon that was responsible for amplifying the impacts. In January, California was met with a different but perhaps not atypical narrative than the rest of the nation when the Palisades and Eatons ravaged some of the same places affected by this week’s flooding. Such areas are designated as “burn scars” and can augment debris and mud flows if it rains. This is because vegetation typically holds water and prevents erosion. But with a protective layer of plants lost to the flames, an area becomes more flood-prone.

“These burn areas are still vulnerable, even though it’s now many months after the fire and there have been flows already,” explains the US Geological Survey’s Jason Kean. He furthers that as the flood progresses down the slopes, it picks up material like rocks, gravel and trees. Together, the debris flows, mudslides and flooding resulted in multiple traffic accidents and a massive sewage leak into the Pacific Ocean.

With fires and now floods leaving their mark on California, it’s clear that the state is no stranger to volatile weather shifts, and neither is the rest of the US.This summer, destructive floods also decimated much of Central Texas, and heat waves set records across the nation. The new, changing and oftentimes detrimental weather patterns seem to leave many unprepared before they can take action.

Unfortunately, this is one of the limitations of current forecasting technology. While most forecasters can pinpoint the general area of impact for a thunderstorm, zooming in on exactly where that place is remains elusive. The problem, however, is in the complex nature of thunderstorms themselves rather than forecasting practices, as they can go from calm rains to walls of water in just hours. This was part of the reason for the slightly delayed response to the Texas floods, as forecasters did not pinpoint the Guadalupe River area until the damage had already been in effect.

However, California seems to have learned from its southern mate, providing forecasts in advance due to the easy-to-track atmospheric river phenomenon. The state began mobilizing its weather teams ahead of the onslaught too. Governor Newsom deployed equipment, resources and staff statewide, including the California National Guard and California Highway Patrol, to monitor the conditions by air and on the road, respectively. In conjunction with these agencies, the Department of Water Resources (DWR) activated its Flood Operations Center and coordinated with state, local and federal partners to monitor river levels. 

The shift to a mainly state-controlled disaster response comes after federal staffing and funding cuts to FEMA earlier this year, which put the US in a precarious situation regarding weather threats. But this does not mean that the collaboration is fully over yet. Federal agencies such as the National Weather Service did activate warnings that local authorities then used to issue emergency declarations. Since the storms were able to be controlled with state resources, federal assistance wasn’t as necessary, though it does represent a reduction in governmental aid compared to prior crises.

With a slew of winter storms expected to bring blizzards and ice to the northern US, and a cold front predicted to cause drastic temperature changes in the southern US, it’s clear the country will see itself solidly in winter territory this week. As the nation heads into a new year, people, much like the weather, will be on edge. Those in California are hoping that 2026 will start and end without natural disturbances, unlike this year’s flames and floods. Perhaps with lessons learned from 2025, federal, state and local agencies can help curtail these weather nightmares and turn them into benign scares instead, whatever the outcome may be.

Read more here:

• Jill Connelly and Rich McKay, Reuters

• Leah Willingham and Jeff Martin, The Associated Press

• Office of the Governor of California, State of California

• Madeline Halpert, BBC News

• Nazaneen Ghaffar, The New York Times

• Rachel Becker, Cal Matters

• Staff, PBS

• Ula Chrobak, Stanford University’s School of Sustainability

• U.S. Government Accountability Office, U.S. Government