Bomb Cyclone To Dump More Water Than in Lake Mead on California

California is expected to receive more rainfall by Friday from an atmospheric river storm than what Lake Mead in Nevada—the largest reservoir in the U.S.—can hold, meteorologists have said, as the state continues to face the threat of flooding.

On Tuesday, Ryan Maue, former chief scientist at the National Oceanic and Atmospheric Administration (NOAA), calculated that as of that morning, 7.7 trillion gallons of precipitation had fallen, with a further 3 trillion gallons expected in the following few days—bringing the 10-day total to around 11 trillion gallons.

At its full capacity, Lake Mead can hold just over 8.5 trillion gallons of water, though its water level has been receding in the past two decades and its actual volume as of January stood at almost 3.1 trillion gallons.

California has been battered by two atmospheric river storms, the first making landfall last week and the second, more powerful, beginning on Sunday.

The latter storm was turbocharged by what is known as a bomb cyclone—when a cold mass of air collides with a warm mass, intensifying a cyclone, bringing more violent winds and a greater likelihood of coastal flooding.

On Sunday and Monday, Los Angeles experienced its third-wettest two-day period on record, with just over seven inches falling, according to the Los Angeles Times.

The storm system caused areas of flash flooding, which created mudslides and saw trapped residents clinging to trees. The flooding prompted California Governor Gavin Newsom to declare a state of emergency for several counties in Southern California on Sunday.

The Associated Press reported that as of Wednesday there had been seven storm-related deaths in the state, citing officials.

Around the same time last year, California was battered by a parade of deadly storms that brought severe flooding. Thousands of homes were left without power and many people were evacuated.

At the time, climate scientists attributed the severity of the storms to climate change pushing more moisture into the atmosphere and energizing weather systems—and this time is no different.

"There's more moisture in the atmosphere, so there's more moisture that falls out of it," Chris Brierley, a professor of climate science at University College London, who specializes in climate modeling, told Newsweek.

"The [increased] severity is something we have projected for quite a while, and is something that we're seeing across the board with storms—that when it rains, it rains more, just purely from a thermodynamic response of a warmer atmosphere and a higher saturation of vapor pressure," he added.

Atmospheric rivers are narrow channels in the atmosphere that can carry a large amount of moisture with them. They form when cold air from the Arctic meets warm, moist air from the tropics, cooling it to form heavy precipitation.

A strong river can transport as much as 15 times the amount of water flowing through the mouth of the Mississippi River, according to the NOAA.