The most potent weather system producing floods in the most potent flood producing region—the high Sierras—makes for an interesting winter and sadness that the advice of those engineers and leaders who called for the building of Auburn Dam weren’t listened to almost 50 years ago as we would now have a 500 year level of flood protection if they had been.
With La Niña, who knows?
Wet or dry, warm or cold -- it's hard to say what weather system will bring this winter.
By Dorothy Korber - dkorber@sacbee.com
Published 12:00 am PST Saturday, December 1, 2007
Call her fickle. Temperamental. Quite possibly schizophrenic. She's the weather phenomenon known as La Niña, and in Sacramento she runs hot and cold, wet and dry.
La Niña, signaled by cooler waters in the equatorial Pacific, sometimes unleashes torrential rain in the Sierra, spawning Central Valley flooding.
But not this weekend. Today and Sunday we can credit La Niña for the dry, arctic air swirling down from Alaska.
A frost warning has been declared this morning in a swath from Redding to Turlock.
In Sacramento, the forecast is for highs in the mid-50s and lows near freezing, said meteorologist Felix Garcia of the National Weather Service. But no rain.
"La Niña is creating this pattern that is blocking us getting low pressure systems, moving them more to the north," Garcia said. "We won't have a chance of rain for the Valley until midweek, and then we'll be lucky if we get maybe an inch."…
"Interstate 80 is just about the pivot point," said Kelly Redmond of the weather service's Western Region Climate Center in Reno. "Statistically, the results in Sacramento are pretty much a wash."
He said that El Niño, La Niña's opposite phenomenon, usually means a wet season for the Southwest – but not a catastrophic one.
"In El Niño years, a lot of the storms come in directly off the Pacific Ocean, kind of flying in from north of Hawaii," Redmond said. "But they don't usually trigger major floods."
Mecurial La Niña, even in a dry year overall, can still cause flooding. Redmond said California's top 10 floods all came during La Niña years.
"In California, the really big floods – the billion-dollar floods – come off the Sierra," he explained. "The Sierra Nevada, when it gets cranked up, is as good a precipitation-generator as you'll find anywhere in the world. And, in the Sierra Nevada, floods seem to be associated with La Niña."
