How heat on the Tibetan Plateau fuels powerful storms in California, half a world away
Heavy rain from an atmospheric river sent the Los Angeles River, normally mostly empty, spilling over its sides in February 2024. Mario Tama/Getty Images The Tibetan Plateau may be on the other side of the world from California, but what happens on this high-altitude landscape in Asia can set off a chain of events that fuels powerful atmospheric rivers with flooding rainfall and heavy snow hitting the U.S.
The Tibetan Plateau, located in Asia, can influence weather patterns thousands of miles away, including in California, despite being on the opposite side of the world. This occurs through a chain reaction where heat on the plateau alters atmospheric conditions, which then travel across the globe to affect weather systems in the U.S. West Coast. The plateau is a vast, high-altitude region averaging 14,800 feet (4,500 meters) above sea level, covering parts of China and neighboring countries. Its elevation and size make it a significant driver of global weather patterns. For example, unusually warm land temperatures over the plateau in early winter can set off atmospheric changes that later strengthen storms in California during the winter rainy season.
California experienced record-breaking precipitation during the winters of 2016–2017 and 2022–2023, leading to widespread flooding and infrastructure damage. These storms were notable because they occurred during La Niña conditions, a climate pattern typically associated with drier winters in California. La Niña is the cooler counterpart to El Niño, part of the El Niño-Southern Oscillation (ENSO), a cycle linked to ocean temperatures in the tropical Pacific. The storms that hit California during these years were atmospheric rivers, long, narrow corridors in the sky that transport massive amounts of water vapor. These events highlighted a gap in seasonal forecasting, as models relying solely on ocean-based events like ENSO failed to predict the extreme precipitation.
Researchers found a link between unusually warm land temperatures on the Tibetan Plateau in early winter and increased late-winter precipitation in California. This connection was established through observations and climate-model experiments. When the Tibetan Plateau warms, it heats the atmosphere above it, altering temperature differences with surrounding regions. These changes can disturb the jet stream, a fast-moving westerly current of air in the atmosphere that steers weather systems. The disturbance travels eastward as a large-scale atmospheric wave, known as a Tibetan Plateau-Rocky Mountain Wave train. By the time it reaches the eastern Pacific, the wave can become unstable, changing atmospheric conditions over the Pacific and strengthening atmospheric rivers that later impact California.
The discovery that early-winter warming over the Tibetan Plateau can amplify atmospheric conditions for strong storms in California offers a new tool for weather forecasting. Traditional models rely heavily on ocean conditions, particularly ENSO, but this study suggests that land conditions thousands of miles away may provide additional clues for predicting extreme weather. Monitoring Tibetan Plateau temperatures alongside ocean and atmospheric conditions could help forecasters better assess the risk of heavy precipitation in California later in the season. This could give communities, water managers, and emergency planners more time to prepare for damaging atmospheric river seasons. The study was published in the journal Science Advances and involved researchers from atmospheric science teams.
The Tibetan Plateau’s influence extends beyond California. Conditions on the plateau also affect weather in other regions, including the *East Asian Monsoon*. Previous research by the same team found a similar pattern where spring temperatures in the Rocky Mountains influenced weather patterns in the U.S. Southern Plains. This highlights the interconnected nature of global weather systems. Incorporating land temperature signals, such as those from the Tibetan Plateau, into forecasting systems could improve the accuracy of weather predictions worldwide. The study emphasizes the importance of considering both oceanic and land-based factors in climate modeling to better understand and prepare for extreme weather events.
