Photo: AP

The United States has faced historic flooding this spring. From the Midwest to California to the Southern Plains, record precipitation has begotten both slow-moving and flash floods.

All this is happening following the wettest 12 month period in U.S. history. But it’s also indicative of bigger issues afoot. Extreme precipitation has become more common due to climate change, raising the risk of floods. A recent analysis from the Union of Concerned Scientists found that the alarm bells are ringing ever louder with a 71 percent uptick in flood watches and warnings this year and that flood alerts have become more common in many parts of the U.S. since 1986. The findings and what we’ve observed this spring show that the country’s infrastructure needs to be shored up fast to deal with a wetter, wilder future.

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“Flood alerts are society’s internal signal that people and property are in harm’s way,” Juan Declet-Barreto, a climate scientist with the Union of Concerned Scientists who did the analysis, told Earther in an email.

The signal has been loud and clear this spring. The U.S. has been absolutely hosed with precipitation in the form of massive snowstorms and abnormally heavy rain. Extreme precipitation has become more common as the planet has heated up, largely because the warmer atmosphere can hold more water. Every region of the U.S. has seen an uptick in downpours in recent decades.

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Not all intense precipitation events lead to floods, but the protracted wet spell leading up to the spring left soils saturated, increasing the odds of flooding. Add in infrastructure—dams, levees, culverts, and other infrastructure meant to deal with rising water—that was designed for the climate of the 20th century and not the supercharged one of today, coupled with more people living in harm’s way, and you have a recipe for natural disaster.

“These factors combine to increase the likelihood of life-threatening floods such as the ones we’ve seen recently in the Midwest,” Declet-Barreto said.

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His analysis underscores this isn’t just a 2019 problem, though. Declet-Barreto pulled 33 years of National Weather Service flood watches, warnings, and advisories. The results show basically every region of the U.S. is seeing more of these alerts. The Midwest is a hot spot, but so is the Southwest, particularly around central Arizona. The types of floods these two regions experience are very different—in the Midwest, it’s usually river floods while Arizona usually sees flash floods and runoff from the desert during the summer monsoon—but the risks they pose are equally challenging society. And if governments don’t improve how they manage stormwater, the impacts will grow ever worse.

“It’s clear we need a coherent and comprehensive federal response to climate change—a response that encourages progress at state and local levels,” Declet-Barreto said.

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Reinforcing infrastructure to handle more extreme rainfall (as well as longer drought periods) is one important fix. Improving flood mapping, including what the federal government considers the 100-year floodplain, as well as reforming programs like the National Flood Insurance Program that encourages people to rebuild in risky places, would also go a long way to protecting lives and property. That’s small comfort to the farmers and others who have lost nearly everything in this spring’s historic floods, but any of those fixes could help ensure the losses won’t be as bad in the future.