The Drought Has Stolen a Year’s Worth of Rain From California
Devastating monsoons have caused flooding across Myanmar over the past week, causing widespread flooding and as many as 27 deaths. Some areas have seen more than 40 inches of rain over the course of just seven days.
It’s not the kind of weather anyone would wish for—especially with fatalities expected to rise—but reading the news from parched California, it’s hard not to get stuck on the rainfall figure. That’s 11 more inches of rain than have fallen in downtown Los Angeles in the last four years, which have been the driest the state has had in 1,200 years. But with the promise of a very strong El Niño potentially bringing a banner winter to the West Coast in terms of rainfall, there’s a lot of talk of how much water it will take to end the drought—and a new study published in the Journal of Geophysical Research: Atmospheres has some answers.
While local rainfall can vary widely in California—Gasquet, which sits on the Oregon border in Del Norte County, averages 95 inches annually, while Death Valley gets 1.5 inches—the study set a baseline of 20 inches a year for the whole state. After four dry years, that’s how much rain California is missing, and there would need to be 200 percent more rain than average to make up for the deficit. While that wouldn’t necessarily mean 40 inches of rain in a week—and the death and destruction that kind of storm brings—it would result in extensive flooding up and down the state.
Using estimates of historic rainfall records and data from NASA’s Tropical Rainfall Measuring Mission satellite, the researchers also looked at California’s overall climate patterns, so as to better understand the state’s long-term weather patterns. Drought, unsurprisingly, is a common occurrence in California, the study found, and the rainfall from the wet years can vary rather wildly—by as much as 30 percent, with El Niño accounting for just 6 percent of the difference.
So despite causing some of California’s most dramatically wet winters—such as the one in 1997–1998, when 20 inches fell in parts of the state in February alone—it’s not the only thing that brings wetter weather. And with close to a third of California’s water coming from snowmelt, the typically warm El Niño winters that tend to bring rain to Southern California could be a wash when it comes to ending the drought. Much like the concrete channel that is the Los Angeles River, waterways in the southern part of the state have been engineered to send excess rain out into the Pacific as quickly as possible. And while those systems are being reconsidered in light of the drought—the Los Angeles Department of Water and Power’s new storm-water capture master plan, for example, suggests the city could collect up to 200,000 acre-feet of water over the 27,000 it currently catches annually—California has to rely on its aging water infrastructure to make the best of whatever nature sends our way this winter.
But with the developing El Niño pattern strengthening in the Pacific, there is some hope that this winter will see rain and snow falling in Northern California too, which could help finally refill the state’s largest reservoirs, located there.