As El Niño approaches, Marin and Sonoma counties get new weather radar to better predict storms causing flooding

As El Niño approaches, Marin and Sonoma counties get new weather radar to better predict storms causing flooding

With a new El Niño watch announced by the National Oceanic and Atmospheric Administration on Thursday, Bay Area weather surveyors are calling on all hands on deck in case next winter mimics the winter we just experienced here in the North Bay.

County public works agencies are installing a new radar system using technology long wanted by the U.S. Navy to help predict potential flooding when atmospheric rivers hit the Pacific Coast.

As part of a $30 million project funded by the Federal Emergency Management Agency, California Office of Emergency Services and the state Department of Water Resources, a radar device has been placed off Airport Boulevard near the Sonoma County wastewater treatment plant. Another project is underway on Pine Flat Road near The Geysers by early 2024. The Sonoma County units will cost $700,000 each.


Marin County The radar station is scheduled to be commissioned at the end of this year on Mount Barnaby, south of Nicasio, at a cost of $2 million. Other sites have been identified in Contra Costa, Santa Cruz and San Mateo counties.

“We are excited to have a few hours advance notice to get resources like sandbags,” said Dale Roberts, project manager and water engineer for Sonoma.

His counterpart in Marin County, Roger Levinthal, the engineer who manages flood control, agrees.

“This system will know where the heaviest rain will fall,” he said.

X- and C-band weather radar stations detect up to 50 and 62 miles away, respectively. It is approximately 10 feet wide and 20 feet high and is mounted on a shipping container. They work by sending radio waves. What bounces back from the clouds is interpreted to show the location and size of the storm and associated rainfall.

They will be It is used to supplement existing National Weather Service stations that aim to reach higher into the atmosphere. These radars track the 10,000 to 15,000 feet elevation range where atmospheric rivers tend to migrate as they approach the coast, causing average flood damage in the state in excess of $1 billion.

The 2022-2023 winter season, which began as a La Niña year in the early months, has resulted in a season that nearly surpasses the El Niño-fueled winter of four decades in history. These are tropical climate phenomena determined by the masses of cold and warm water, respectively, off the shores of South America.

The winter of 1982-83 was filled with 50.6 inches of rain.

By comparison, Santa Rosa received 43.1 inches, with an average of 28.8 inches, according to the National Weather Service. Napa got 31.3 inches of rain this water year, 13 inches short of the record. Normal is 24.4 inches.

Marin County endured 39 inches of rain, about 7 inches more than the normal amount of precipitation. The record is 61.9 inches.

So far this year, California has seen 31 atmospheric rivers. Under most conditions, atmospheric rivers account for the majority of damage, resulting in 6,650 insurance claims in Sonoma County and 3,152 in Marin, according to project engineers.

Ghee below the gates

The National Oceanic and Atmospheric Administration (NOAA) is preparing for the 2023-2024 El Niño winter. Although the Bay Area is on the cusp of equal chances of experiencing dry or wet conditions, more often than not it provides more precipitation for our area.

“Historically, when you look at 20 states, they tend to favor wetter conditions in Northern California, especially later in the season,” Michele Llorieux, a climatologist at the National Oceanic and Atmospheric Administration (NOAA) who specializes in El Niño, told the Business Journal. winter”. “The odds are in her favor.”

Currently, the El Niño phenomenon is increasing, with a 62% probability of the weather phenomenon developing between May and July. This comes a few years after the La Niña phenomenon. Both are often described as bringing opposite results from one end of the Pacific coast to the other.

In El Niño years, there are greater possibilities for a more active pattern of heavy precipitation from the Bay Area down to Southern California, leaving the Pacific Northwest drier.

But climate has proven not to be a perfect science. For example, La Nina faded away this year long before most atmospheric rivers took over the landscape.

It was the third La Niña. “That’s why it got a lot of attention,” Lorioux said.

NOAA scientists will continue to monitor the potential development of El Niño this year. They plan to release a monthly update on May 11.

Susan Wood covers law, cannabis, production, technology, energy, transportation and agriculture as well as banking and finance. Susan has worked for 27 years at a variety of publications including the North County Times, Tahoe Daily Tribune, and Lake Tahoe News. Contact Wood at 530-545-8662 or

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