Extreme Rainfall Set To Break Los Angeles Record

The amount of rain Los Angeles has experienced recently is on track to become the highest amount since records began.

As of Monday, the National Weather Service (NWS) station in the Californian city said that since October 2022, downtown Los Angeles had received a total 52.46 inches of rainfall, making it the second wettest two-year period on record. It noted that the period of measurement still had six months to go.

The only wetter period for the city since records began in 1877 was between October 1888 and September 1890, when 54.10 inches fell.

“When you consider the records since 1877 in downtown L.A. … the second [largest total] is hugely significant,” Joe Sirard, a meteorologist at the NWS station in Oxnard, told the Los Angeles Times. “We’re obviously way, way, way above normal for two years in a row now. For a dry climate like the Los Angeles area, it’s huge.”

States on the West Coast have faced several bouts of precipitation over the winter, having been subjected to a “prolific series” of atmospheric river storms from the Pacific.

One such storm in February caused areas of flooding and mudslides, as well as several deaths, prompting Gov. Gavin Newsom to declare a state of emergency for several counties.

The first wave of the storm made landfall in southern California, an area deemed at high risk of flooding by the Federal Emergency Management Agency.

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

The NWS station in Los Angeles said that the 2022-2023 water year was the seventh wettest on record, and had the eighth wettest January and seventh wettest March due to major winter storms. Tropical Storm Hilary contributed to the wettest August on record last year.

One of the winter storms to impact the city in February this year produced the fourth-wettest day of that month since records began, bringing 4.1 inches of rain. Rainfall from a storm last week brought 2.1 inches of rain to the city.

Experts agree that as the climate gets warmer on average, more energy will be pushed into the atmosphere, energizing weather systems and making them more erratic. This means that extreme weather events will occur with greater severity.

California sits on the path of an atmospheric river—known colloquially as the Pineapple Express—which is a narrow channel of air that can carry a large amount of moisture. It forms when cold air from the Arctic meets warm, moist air from the tropics, cooling it to produce 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 National Oceanic and Atmospheric Administration.

With climate change energizing weather systems, atmospheric river storms capable of producing higher amounts of precipitation are expected to become more common.

“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, previously 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.

There is a strong chance that, in the short term, Los Angeles will experience more precipitation. There is a 40 percent chance of rain from a storm system on Friday, while in the coming six to 10 days, above normal rainfall is forecast as a possibility for the region.