After recently facing the toughest drought in over 1,00 years, California, the nation’s richest and most populous state went through devastating floods that culminated in the Oroville Dam disaster that forced 250,000 residents to evacuate.
Added to these two major climate events are the huge wildfires that have devastated many areas of the state, adding insult to injury when torrential rains beat on barren hillsides, turning them into deadly mudslides that engulf homes and residents alike.
California residents can expect even more of these wet-and-dry climate events, according to research published in Nature Climate Change today. UCLA climate scientists suggest that the frequency of these rapid, year-to-year swings from extreme dry to wet conditions — which the study authors dub “precipitation whiplash events” — may become more common in California’s future as a consequence of anthropogenic climate change.
“Collectively, our findings suggest that anthropogenic warming will bring about large increases in the frequency of California hydroclimatic extremes similar or greater in magnitude to those that have historically caused widespread disruption,” researchers write in the study.
Actually, the study says the frequency of these so-called whiplash events will double in Southern California by the end of this century, reports USA Today.
UCLA climate scientist Daniel Swain, the lead author of the study, said this means that instead of about four whiplash events occurring in a century, the number could go up to eight events.
Interestingly, these whiplash events are very concerning because of the wet extremes which are already amplifying the variable precipitation across the state. This will place the state’s infrastructure under a great deal of stress, according to ZME Science.
And of particular concern would be a repeat of the infamous 1862 flood that likely killed thousands of people and left the Central Valley under water. A repeat “would probably lead to considerable loss of life and economic damages approaching a trillion dollars,” the study said. And that is about a third of California’s Gross Domestic Product (GDP).
The dire warning coming out of this study
As the study points out, most people won’t notice anything is amiss if they are just looking at statistics like average annual rainfall, simply because dry and wet periods will largely cancel each other out. But they will have a major effect on Californians.
“These are actually huge changes occurring; they’re just on opposite ends of the spectrum,” Swain said. “If you only look for shifts in average precipitation, you’re missing all of the important changes in the character of precipitation.”
And it is the full spectrum of changes in precipitation that are worrisome. Those who manage California’s water supply and protect residents from wildfires, floods, and other natural disasters should be planning for those changes, says Swain. The researchers also predict California’s wet weather may become even more concentrated in winter months than it already is, while storms in the spring and fall become less likely and less frequent.
The study ends with a dire warning: “Moreover, we report a substantial increase in the projected risk of extreme precipitation events exceeding any that have occurred over the past century—meaning that such events would be unprecedented in California’s modern era of extensive water infrastructure.”
“Few of the dams, levees and canals that currently protect millions living in California’s floodplains and facilitate the movement of water from Sierra Nevada watersheds to coastal cities have been tested by a deluge as severe as the extraordinary 1861–1862 storm sequence.
