This story was originally Appeared in Grist is part of climate desk collaboration.
California is well aware of the large fluctuations between wet and dry seasons. The ‘Atmospheric River’ storms that hit the state this winter are part of a system that has left drought periods long interrupted and heavy rainfall. In fact, it provides 30-50% of all precipitation on the West Coast.
A stormy parade that has hit California in recent months has dropped more than 30 trillion gallons of water on the state, refilling reservoirs that have remained empty for years, and filling mountain towns with snow.
But climate change is making these storms wetter and more intense, increasing the risk of flooding in California and other states on the West Coast. This is not only because the air over the Pacific holds more moisture as seawater warms, creating large amounts of rain and snow, but also because rising temperatures on land will cause more rain as rain in the future. Because it can rain. dangerous flood.
A series of storms that hit the state this week have smashed snow records and crossed levees across the state, only to underscore this danger.
“The impacts are cascading,” said Tom Collingham, a researcher at the Scripps Institution of Oceanography at the University of California, San Diego. “As you push the river harder and push the flood protection system harder, there is an exponentially increasing impact. To do.”
An “atmospheric river” is a long, narrow ribbon of moisture that carries water vapor from the tropics to the high-latitude landmass. One of the best-known examples is the “Pineapple Express,” which sails east across the Pacific Ocean from Hawaii and lands on the West Coast. The term atmospheric river dates back to the 1990s and became fashionable because of the large amount of water these ribbons can contain: one ribbon moves more than twice as much water through the sky as the water that flows out of the Amazon estuary. You can. , the largest river in the world by volume.
As Pacific ocean temperatures and temperatures warm, storms hitting the west coast will retain more moisture, resulting in longer, heavier rains. Starting off, California is swinging in a pendulum between extreme drought and extreme rain. Studies show that as the climate warms, atmospheric river events will make up an ever-larger share of California’s overall water budget, dumping water faster than the state can absorb it.
“Around the world, it will be wet in some places and dry in others. California seems to have both,” Corringham said. “Longer periods of drought followed by rain will make these events more intense. In terms of water management, that is not what you want.”
