New Scale for Ranking Atmospheric River Storms Like Hurricanes Is Developed by UC San Diego Researchers, State Officials

The announcement of a new scale to measure atmospheric river storms, which cause some of the West Coasts's heaviest rains, was made in 2019. (Credit: Kent Nishimura / Los Angeles Times)

The announcement of a new scale to measure atmospheric river storms, which cause some of the West Coasts's heaviest rains, was made in 2019. (Credit: Kent Nishimura / Los Angeles Times)

Marty Ralph was sitting in a San Francisco restaurant a couple of years ago when the morning forecast came on the TV, showing the typical weather symbols indicating what the week ahead would bring: a sun, a cloud, a rainy cloud and a darker, more ominous rainy cloud.

Ralph, the director of the Center for Western Weather and Water Extremes, knew that at the end of the week, an intense atmospheric river storm was coming through the area. But he didn’t think the TV meteorologists could convey that very well with the icons on the screen. So he and a team of researchers got to work creating a ranking system that would be more helpful.

On Tuesday, researchers announced a new scale to describe the strength of atmospheric river storms, weather events that cause many of the West Coast’s heaviest rains.

Unlike other scales that focus on potential damage — such as the Fujita scale for tornadoes or the Saffir-Simpson scale for hurricanes — the atmospheric river scale will also characterize how beneficial storms can be for the water supply among California and other Western states, according to UC San Diego’s Scripps Institution of Oceanography. It was created in collaboration with the Department of Water Resources and the National Weather Service.

Read the full story at LATimes.com.

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