Monday November 2, 2026
USA Today —
The rivers in the sky hold the key.
The strength, location and duration of atmospheric rivers – ribbons of water vapor that extend thousands of miles from the tropics to the western United States – will be the deciding factor in how much rain and snow falls in California this winter, and whether a disastrous “ARkStorm” flood could conceivably occur, experts told USA TODAY.
“Atmospheric rivers are the wild card for this winter,” Scripps Institution of Oceanography research meteorologist Marty Ralph told USA TODAY. “If we get atmospheric rivers back to back, that sets the stage for potential flooding.”
The El Niño powering up in the Pacific is prompting fears of a calamitous California winter, with potential flooding of historic proportions.
Could it cause an “ARkStorm” scenario? “I am concerned about this winter,” Daniel Swain, a climate scientist with the University of California Agriculture and Natural Resources, told USA TODAY. “Due to the very strong El Niño, the risk of a severe ARkStorm-like flood resulting from weeks of heavy precipitation is more likely in a year like this one.”