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Better Atmospheric River Forecasts Are Giving Emergency Planners More Time to Prepare for Flooding

/in , , /by /Scientific Americanby F. Martin Ralph

I was eating breakfast on a Monday morning at Sears Fine Food in downtown San Francisco, casually watching the local five-day weather forecast on a television screen behind the counter. A little symbol along the bottom showed a happy-looking sun for the rest of the day. Wednesday had a friendly-looking cloud and a few raindrops, and Thursday had a dark, threatening cloud with heavier drops.

I knew Thursday’s conditions would be much rougher than the symbol conveyed. I had been studying detailed satellite data and weather models, and they indicated that a major atmospheric river (AR) was likely to hit the city. The symbol was completely inadequate for communicating the threat of the approaching storm.

 

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Stubborn La Niña Looks Like It May Stick Around for a Rare Third Year

/in , , /by /Los Angeles Timesby Paul Duginski

A stubborn La Niña climate pattern in the tropical Pacific is likely to persist through the summer and may hang on into 2023, forecasters say.

La Niña has been implicated not only in the unrelenting drought in the U.S. Southwest, but also in drought and flooding in various parts of the world, including ongoing drought and famine in the Horn of Africa.

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With a Third Year of Drought, Southern California Facing a Hot, Dry Summer

/in , , /by /Los Angeles Timesby Paul Duginski

Memorial Day, the unofficial start of summer, is Monday. What’s in store for the upcoming season of beach days and barbecues in Southern California?

To start with, it will be dry. That’s not just because California’s Mediterranean climate means rain mostly falls during a few wet winter months, but because the state is in its third year of drought.

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Opinion: Pages From a Farmer: And Then the Rain Never Came

/in , /by /Napa Valley Registerby Carine Hines

Bombtober” some called it, when an incredible atmospheric river drenched the drought-stricken soils and mountains of California. We all danced and rejoiced, and much thought, and may still think, that we made it through the recent stretch of drought. Was it realistic to believe that a few days of heavy rain could undo the harm of months and years of drought? Only if it continued to rain, but it never did.

This winter we experienced the driest January and February in recorded history, which are typically our wettest. And we will not have a “Miracle March”.

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San Diego Research Links Oroville Dam Crisis to Global Warming

/in , , /by /KPBSby Thomas Fudge

The Oroville Dam in northern California is the nation’s tallest dam and it creates the state’s second-largest reservoir. In February of 2017, an atmospheric river dumped a huge amount of snow then a huge amount of rain into the reservoir’s watershed.

A 30-foot wall at the top of the dam, called the weir, nearly gave way to the volumes of water and 188,000 people had to be evacuated.

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Where California’s Key Reservoirs Stand After the 2nd Driest January Ever

/in , , /by /SF GATEby Amy Graff

California hasn’t seen rain in over a month, and some of the state’s key reservoirs are starting to be impacted.

Shasta Lake, the state’s largest reservoir, was at 54% of its historical average as of Feb. 9, compared to 72% last year, the California Department of Water Resources said. San Luis Reservoir on the eastern slope of the Diablo range is at 59% of its historical average, compared to 71% last year.

Other reservoirs are up from where they were at this time last year.

“This would be expected given that last year was the 2nd driest year for CA in our observed record and the 2020-2021 two year period set a new record for dryness,” Michael Anderson, the state climatologist for the Department of Water Resources, wrote in an email.

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What Is an ‘Atmospheric River’? These Rivers of Wator Vapor Can Extend Thousands of Miles.

/in , , /by /USA Todayby Doyle Rice

Often in the winter, you’ll hear that “atmospheric rivers” are causing big weather problems along the West Coast. But what are they?

Made visible by clouds, these ribbons of water vapor extend thousands of miles from the tropics to the western U.S. At 250 to 375 miles wide, they provide the fuel for massive rain and snowstorms that can cause flooding along the West Coast.

In general, atmospheric rivers pick up water vapor from the warm, moist air of tropical regions and then drop the water over land in cooler regions as rain or snow.

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Dry January Takes a Toll on Promising Start to Water Year

/in , , /by /AgNet Mediaby Brian German

The second manual snow survey for the current water year demonstrated the impact that dry conditions in January have had on California’s snowpack. The Department of Water Resources (DWR) conducted the survey at Phillips Station earlier in the week. While the measurements were relatively strong, there is still concern for the rest of the season as statewide water storage levels sit at about 76 percent of average.

“For our survey today, we recorded a snow depth of 48.5 inches and a snow water content of 19 inches. That results in 109 percent of average to date and 78 percent of the April 1 average here at this location,” said Sean de Guzman, Manager of DWR’s Snow Surveys and Water Supply Forecasting Unit. “That one dry month of January basically wiped out whatever head start we had as we head towards the end of winter. We still have about two more months to build up our snowpack, but we all need to be prepared for a third consecutive dry year.”
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California Drought: Sierra Nevada Snowpack Falls Below Average After Dry January

/in , , /by /The Mercury Timesby Paul Rogers

Like the 49ers fourth-quarter lead in Sunday’s NFC Championship game, California’s once-impressive Sierra Nevada snowpack is steadily shrinking.

Only a month ago on New Year’s Day, after big atmospheric river storms in October and December, the statewide Sierra snowpack stood at an impressive 168% of normal for that date, boosting hopes that the state’s severe drought might be ending.

But on Monday, the magnificent became mediocre: The snowpack had fallen to just 93% of its historical average.

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February Could Be the Make-Or-Break Month for California’s Drought

/in , , /by /ABC 10by Monica Woods

California is nearing that make-or-break point to pick up some rain and snow totals. January has turned out to be a total bust for big storms, continuing that winter whiplash of wet to dry weather.

Almost all the gains we’ve made reducing the severity of our two-year drought came from storms in October and December. In October, those gains were from one big atmospheric river sitting over the state for days. December saw multiple storms ending in a record setting snowiest month for the Sierra.

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