Reservoirs in Northern California poised to swell with coming storms

With two big storm systems poised to hit the Bay Area this week, California is looking to see another spike in state reservoir water levels in the coming days. 

Many Northern California reservoirs are sitting at higher water levels than we saw after last winter's historic atmospheric rivers blew through the Bay Area. Nearly all reservoirs in NorCal are way beyond their historical averages, except for Trinity which is now sitting at 96% of its historical average. 

The Shasta and Oroville reservoirs caught most of the attention last year, as both swelled far past their historical averages. The two Northern California reservoirs are both sitting over 120% of their historical averages as of Tuesday. Take a look at the comparison between reservoir levels in March 2023 versus this week:

Only one reservoir dropped in levels over the past year, and that was New Bullards Bar by one percent. 

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March 2023 Reservoir Levels ((Courtesy of CADWR))

The California Department of Water Resources says that controlled water releases from Oroville Dam's main spillway will begin Wednesday as the storms hit. The aim of the releases is to prevent flooding near the dam. 

The full list of current reservoir data can be seen below:

Though plenty of rain has come our way over the last year and flushed tons of water into our reservoirs, CADWR says that snow pack levels are still below average. Some of the storms heading into Northern California this week could drop more snow in those higher elevations, particularly over the Sierra.