Warm Tibetan Plateau Fuels Record California Storms

A new study in Science Advances shows that unusually warm land temperatures on the Tibetan Plateau in early winter can set up atmospheric conditions that amplify powerful atmospheric rivers, delivering record‑breaking rain and snow to California and the West Coast. Researchers first identified a statistically significant link between early‑winter plateau temperatures and late‑winter precipitation in California. To test causality, they ran global climate‑model experiments: when the model was driven only by sea‑surface temperatures it failed to reproduce the extreme precipitation, but when observed plateau temperatures were used to initialize the model it reproduced both the plateau warming and the California rainfall. The mechanism involves the plateau’s heat altering the jet stream, producing a large‑scale wave train that destabilises over the Pacific and strengthens atmospheric rivers. Incorporating plateau temperature signals could give forecasters additional lead time to warn communities, water managers and emergency planners about potential flooding.