Study Links Intense Downpours, Flash Flooding to Heat

By Mark Leberfinger, AccuWeather.com Staff Writer

June 27,2015; 9:52PM,EDT

 

 

The world may see an increase of intense downpours that contribute to flash flooding, new research says.
Researchers at the University of New South Wales claim that higher temperatures enhance the intensity of rainfall that can lead to flash flooding.
The research, published earlier in June in the journal Nature, found that storms could be more destructive when there is heavy rainfall during periods of higher temperatures.
The new research may help forecast potential flash-flood events, AccuWeather Senior Meteorologist Jason Nicholls said.
The researchers tabulated data from 79 monitoring stations in Australia between 1955 and 2005.
Then-Australian Prime Minister Julia Gillard views flood damage from a helicopter above Wagga Wagga, Australia, Wednesday, March 7, 2012. (AP Photo/Andrew Meares, Pool)
If future temperatures rise 5 C (9 F), there would be a 5 to 20 percent increase in rain during floods as compared to today's temperatures, the researchers predicted.
Warmer air can hold more water vapor than cold air, said Nicholls.
The increased volume of water that a warm air mass can hold can increase the likelihood of heavy rain, capable of inundating the area.
"Warmer air masses also tend to be more unstable or offer more favorable conditions for convection," Nicholls explained.
Downpours and heavy rainfall tend to be fairly common in thunderstorms worldwide, but not every thunderstorm produces downpours, he said.
"You can see some evidence of the idea of more rain in warmer climates just by looking at normals. The tropics receive much more rain annually than the arctic which receive little precipitation. In fact, Antarctica is technically a desert, just a cold one," he commented.
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Nicholls, an experienced global forecaster, said he has frequently noted extreme heat in Australia ahead of frontal boundaries, which is usually broken by strong thunderstorms sometimes with heavy rainfall.
"Any information like this would be helpful," he continued. "You could use this in addition to the weather models that may not consider that kind of data."