Be careful what you wish for. Californians have been praying for rain and have been blasted by a rampaging river.
This isn’t just a normal river. It is an atmospheric river. Scientists used to call it a “moisture plume”, residents call it a “Pineapple Express” but that doesn’t convey how blasted powerful these things are! Imagine a river of water, larger than any river on Earth, flowing through the sky then dumping on your head.
These rivers start off as storms in the tropics. You’ve seen the parade of hurricanes and tropical storms that march through tropical waters. They generate enormous amounts of moisture and, thanks to the spin of the Earth, this moisture gets spun away from the equator to the poles. They are typically thousands of miles long, a few hundred miles wide and flow a few miles high in the sky. Then they hit the cold air over land and all that water crashes down to earth.
Storms march across the tropics and generate rivers of moisture. Source: NASA
California really needs this rain. Despite all the wonderful promises, El Niño has been a disappointment. It was supposed to bring lots of rain and some dreamers even fantasized that it would end the five-year drought. Instead, by the end of the December/January/February winter season, there was below average rainfall. The state’s reservoirs are at 67% of normal. Worse yet, its snowpack is only 79% of normal, down from 113% at the end of January. California’s major source of water is snowmelt and the resulting river flow.
California is still in drought
The good news is that typically El Niños produce a “Miracle March” or “Amazing April”, a last stormy flurry of the West Coast wet season. This March is starting off with the lovely miracle of an atmospheric river that is expected to bring a lot of rain and up to three feet of snow for the high mountains. It also brought flash floods and some mudslides, but on the plus side (if you are an aging surfer like Evelyn) it is sweeping in some major waves.
California will share the wealth, Washington, Oregon, the Intermountain West, even parts of British Columbia will get rain and snow. The “Miracle March” will storm inland.