The Role Of Climate Change In Utah And Arizona’s Deadly Floods

Climate change isn’t what’s causing the deadly flash floods in Utah and Arizona this week, but it’s part of what’s making them so catastrophic, one expert warned.

As of Wednesday evening, at least 18 people have been killed by intense flooding near the Arizona-Utah border that began Monday, while others remain missing, including 6-year-old Tyson Lucas Black.

Flooding that powerful is an example of how the warmer atmosphere turns ordinary weather events into more extreme ones, Kevin Trenberth, a senior scientist with the National Center for Atmospheric Research, told The Huffington Post.

“The climate change aspect of this is that the atmosphere is warmer, and for every 1 degree Fahrenheit increase in temperature, the atmosphere can hold about 4 percent more moisture,” he explained.

“When the right weather system comes along,” such as the storm above Utah and Arizona, Trenberth said, “that weather system can be thought of as a device for reaching out — quite a ways at times — and grabbing the available moisture and bringing it in and dumping it down.”

“Climate change is not the cause, but it is — I’m tempted to say — a minor contributor,” he added. “Even that minor contribution can be that straw that broke the camel’s back.”

Prolonged drought in Utah and Arizona, which are facing moderate to severe dryness in about 90 percent of each state, is also partly responsible for the water buildup, Trenberth explained.

“In the case of a drought, the ground is often not receptive to moisture,” he said, explaining that lighter, more frequent rains would be absorbed more easily. “Not much of it soaks in, and it all tends to accumulate, and the next thing you know, you’ve got a flood on your hands.”

Such extreme floods are occurring —> Read More