West Coast facing another ‘atmospheric river’ of weather-related news

Normally, we here at Water Resources prefer to stay off the topic of “weather” and, instead, stick to longer-term climate-related conditions, particularly drought.

The 2016-2017 “water year” — officially October 2016 to September 2017 — isn’t letting us do that. It’s just been too darned wet out there to avoid observing that current weather conditions are greatly impacting long-term climate conditions.

Two big, unavoidable weather stories are happening right now: The “biggest storm of the winter” that is now hitting southern California, and the more northerly disturbance following it that will push a lot of water where none is needed right now, the area of the Oroville Dam.

While the extremely wet Western winter has driven drought off the map in much of northern California, SoCal has been much drier. The sole remaining sliver of “extreme drought” in the Golden State, according to the U.S. Drought Monitor, is in the south.

That status may be changing right now. Greater Los Angeles could get between five and seven inches of rain before the weekend is out. Hundreds of flights out of LAX are being cancelled. And the weekend rush hour commencing in less than two hours is guaranteed to be every traffic cop’s worst nightmare.

The bigger drama, however, remains to the north at the Oroville Dam, where a rain-and-runoff-damaged spillway has caused grave concerns for residents as far downstream as Sacramento.

The latest “atmospheric river” poised to hit northern California is expected late Sunday into Monday and perhaps five inches of rain could fall in the Oroville Dam region. Nevertheless, California Department of Water Resources officials are feeling much better about the dam’s condition than they were just a few days ago.

“The threat level – it is much, much, much lower than what it was on Sunday,” said CDWR Acting Director Bill Croyle to reporters on Thursday.

The Oroville crisis prompted some considerable interest among local media about the condition of Arizona dams.

As ADWR Director Tom Buschatzke explained to ABC News 15 earlier this week, Arizona’s biggest dams — including the two mega-dams on the Colorado River and the Salt River Project dams — are inspected by the federal Bureau of Reclamation.

The ADWR dam-safety program regularly inspects 106 dams designated as “high-hazard potential” dams around the state, but none of which approaches the size of the 770-foot Oroville Dam, or the 3.5 million acre feet of water held behind it.