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Atmospheric rivers past and present

Flooded strawberry fields in Salinas California.

The voluminous rains brought to California by a series of atmospheric rivers have leveled off for the time being, reports the Washington Post. Atmospheric river eases after bringing serious flooding to California – The Washington Post

“Beyond that, quiet weather looks likely for the next few days,” said the article, dated March 15. “Some rain showers, mostly light in nature and widely scattered, are probable late Thursday into Friday. Computer models project the next atmospheric river will affect the state early next week, with another round of significant precipitation.

“After that, it looks like a continued parade of storms will persist over the northeast Pacific. That will send low pressure systems into coastal Oregon and Washington, each of which could draw filaments of moisture and steer atmospheric rivers into the coast of California. There’s no telling when this pattern may let up.”

richard smoley produce blueprints

One of the hardest-hit areas is the Pajaro Valley, located roughly halfway between Monterey and Santa Cruz.

On Saturday, March 11, a levee was breached, flooding the northern side of the valley: the three main crops affected were iceberg and romaine lettuce and strawberries. Nearly 2,000 residents of the town of Pajaro were evacuated.

Planted crops destined for harvest from mid-April to mid-May have been flooded, creating likely losses in both yield and planting. On Wednesday the 15th, California Strawberry Commission president Rick Tomlinson issued a statement which read in part:

“For the farms that were flooded, this catastrophe hit at the worst possible time. Farmers had borrowed money to prepare the fields and were weeks away from beginning to harvest. Disaster relief and emergency financial assistance will be critical for both the residential community and the farming operations.

“California strawberry operations, most of which are multi-generational and family-owned, will remain vital to the damaged areas during the recovery and well beyond.

“California’s 400 family strawberry operations create 70,000 jobs in the state and invest 97 cents of every dollar back into the community. That commitment will only grow as the damaged area recovers. Despite the challenges, there will be increased shipments of California strawberries from Oxnard and Santa Maria to stores across the country to keep up with high demand.”

As astonishing as this weather may seem, it is a recurring pattern in the state.

The most damaging atmospheric river in the state’s recorded history hit on Christmas Eve, 1861, and lasted for 43 days. In those days, California agriculture was dominated by cattle ranching: an estimated one quarter of the state’s 800,000 cows died. Sacramento was submerged by 10 feet of brown water, forcing the state government to move to San Francisco for 6 months.

“Massive floods have struck California every 200 years or so, according to analysis of sediment deposits left by the torrents in four widely separated locations,” according to Scientific American.

“Different dating methods used at the sediment sites have varying margins of error, but the midpoints align fairly well. If the pattern holds, the state could be due for another catastrophe,” Scientific American predicted in 2013.

The article goes on to say, “smaller atmospheric rivers are not all bad; between 1950 and 2010 they supplied 30 to 50 percent of California’s rain and snow—in the span of about 10 days each year.”

Atmospheric rivers are not peculiar to California: they can occur on the west coasts of any continent. “The next megaflood could occur in Chile, Spain, Namibia or Western Australia,” notes Scientific American.


Richard Smoley, contributing editor for Blue Book Services, Inc., has more than 40 years of experience in magazine writing and editing, and is the former managing editor of California Farmer magazine. A graduate of Harvard and Oxford universities, he has published 12 books.