Original publication by Benji Jones for vox.com on 11 January 2023
California’s floods reveal a likely climate change symptom: Quick shifts between opposing weather conditions.
In less than a week, the story about California’s weather shifted dramatically. Just before New Year’s Eve, the state was running out of water following two decades of severe drought. Then, it started to rain and rain. Over the last two weeks, California was battered by a series of atmospheric rivers — narrow corridors of water in the sky — that utterly drenched the region, killing people and damaging homes and highways.
From extreme drought, the focus on California has quickly pivoted to extreme floods.
There’s a term for this: weather whiplash. It generally describes a quick shift from one weather extreme to another. And California is far from the only region to experience the effect. Places like Dallas and Michigan, as well as parts of Europe and Asia, have all experienced their share of whiplash, which often produces catastrophic results.
A key question now is whether weather whiplash is getting worse as the planet warms — and how that might complicate disaster readiness.
Whiplash weather, briefly explained
The term “weather whiplash” has been around for at least a decade, and it means what it sounds like: a quick shift between two extreme and opposing weather conditions. From drought or fire to floods, from severe cold and snow to heat waves.
California’s current crisis is a perfect example. The state is experiencing its worst drought in roughly 1,200 years. Millions of residents have been asked to cut their water usage. But the ongoing storms turned the extremes around: Much of the state has received rainfall amounts that are 400 percent to 600 percent above average, resulting in some of the worst floods in California history. (So far, the water hasn’t been enough to quench the drought, and there isn’t sufficient infrastructure to capture the flood water for later use.)
Last summer, Dallas experienced a similar whiplash effect. For days on end, temperatures soared above 100 degrees. More than two months passed with no rainfall. Then a rainstorm struck, dumping more than a foot of water in parts of the city in half a day. A similar story played out in the Southwest, where exceptionally warm weather fueled wildfires, which were followed by exceptional quantities of rain.
Temperatures can whiplash, too. In late December, temperatures plunged into negative double-digits across much of the Midwest and East. More than 50 inches of snow fell on Buffalo, New York, killing more than two dozen people. Then, in a matter of days, temperatures in many of those places soared — to 30, 40, and, in some cases, more than 70 degrees Fahrenheit. Some cities even set warm temperature records.
It may seem like these whiplash events are becoming more common, though perhaps that’s because they’re fresh in our minds. So are they?
Climate change could make whiplash weather more common
Yes, some scientists say: Climate change could be making whiplash events more frequent in the decades to come, though there are some key uncertainties.
A study published in 2022, for example, found that while whiplash weather events haven’t become more common in recent decades, they’re likely to increase in the future due to warming. Another paper, from 2020, found that in certain regions, “seesaws” between drought and intense rainfall have become more common (the study doesn’t say whether climate change is the culprit).
“These sudden shifts are highly disruptive to all sorts of human activities and wildlife, and our study indicates they’ll occur more frequently as we continue to burn fossil fuels and clear-cut forests,” said Jennifer Francis, the lead author of the 2022 study and senior scientist at the Woodwell Climate Research Center.
There are two main reasons why climate change could be behind whiplash.
When the air warms, it can suck moisture out of the ground, drying out vegetation. That can cause drought and wildfires. But warm air also holds more water — about 7 percent more for every degree Celsius, as Vox’s Neel Dhanesha writes. “The result is an atmosphere that takes longer to get saturated with water, which means fewer rainstorms, but when they do occur, those storms dump more water at once,” Dhanesha explains.
Parched soil has a hard time absorbing water, so rain just runs off into rivers and onto roads, causing quick-forming floods. (That’s one reason why floods don’t simply relieve droughts; the land can’t easily absorb all of that water.)
Whiplash between hot and cold temperatures in the Midwest, meanwhile, can result from shifts in the polar vortex, a low-pressure area of swirling cold air around the North Pole, according to Judah L. Cohen, director of seasonal forecasting at the climate consulting firm Atmospheric and Environmental Research.
You can think of the polar vortex like a spinning top, he said, and warming in the Arctic can throw it off balance. That causes the vortex to wobble toward the US, spilling cold air south, away from its center of rotation.
What creates whiplash is when it snaps back, he said. “The polar vortex stretches out like a rubber band,” he said, referring to the cold air seeping South into the upper US. “Then the rubber band snaps back.” The cold air is then replaced by warm air coming from the equatorial region, he said.
Not all scientists agree with Cohen that climate change will make vortex-related cold snaps more common. “I’m in the minority saying that climate change can lead to weather whiplash in the winter months,” he said.
That’s partly because the idea of cold outbreaks complicates the broader story of climate change, he said — that rising greenhouse gas emissions are just making the planet warmer. They certainly are, he said, but climate change can cause other weird effects, and this is likely one of them. Warming is not the only effect, he said.
Perhaps it goes without saying, but exceptionally cold winter days don’t undermine the evidence of climate change. Neither does severe flooding indicate that California won’t continue to suffer from drought. Sometimes climate change can mean getting the worst of all weather extremes — a brutal reality we need to brace for.