California water officials and forecasters say the state is more prepared heading into winter after last year’s “miracle” year that delivered a deluge of water and snow to its drought-depleted reservoirs.
After three years of drought, the state emerged from the dry weather beginning with a series of storms in December 2022 and was able to provide a full allocation of water to cities and counties, and even more, in some cases.
A rapid change in weather patterns in 2023 boosted the state’s water recovery.
A series of nine atmospheric storms in December 2022 and January 2023 were followed by back-to-back storms and tropical storm Hilary that drenched Southern California in August.
From October 2022 to March 2023, California received 153 percent of average precipitation, making it the sixth-wettest winter on record for the state, according to the state’s water department.
For the past few years, California experienced weather patterns attributed to the La Niña climate, which is characterized by cold ocean water and drought.
But ocean temperatures warmed considerably this year, ushering in an El Niño climate pattern marked by warmer water and wetter weather.
As a result, the past winter storms boosted water supplies to the California State Water Project, the nation’s largest state-built water and power system, which provides water to 27 million people.
As part of the project, Lake Oroville levels recovered and had the single-biggest increase in the project’s history, capturing 3.5 million acre-feet of water in reservoirs since Dec. 1, 2022. One acre-foot equals about 326,000 gallons of water, or enough water to flood a football field 1 foot deep.
The lake, located about 75 miles north of Sacramento, is at 136 percent of average starting this water year, which runs through Sept. 30, 2024. The lake sits behind Oroville Dam, the tallest in the United States.
“Between Dec. 1 [,2022,] and the end of the spring snowmelt, Lake Oroville increased more than 240 feet in elevation and gained over 2.5 million acre-feet of water,” Ted Craddock, deputy director of the State Water Project, said on Oct. 3. “That’s the largest increase we’ve seen in Lake Oroville storage in a season since the lake was built in the 1960s.”
At this time last year, Lake Oroville was at just 64 percent of historical averages and held only 1.2 million acre-feet of water, Mr. Craddock said.
The San Luis Reservoir, jointly operated by the state and Merced County, located along the coast in central California, is at 190 percent of the historical average, up from 67 percent this time last year, he said.
But levels of groundwater, which is water held underground in the soil or rock, only partially recovered with the deluge of precipitation in 2023, according to Paul Gosselin, deputy director of sustainable groundwater management at the state’s water department.
“This year, groundwater levels began to recover a bit, but only partially,” Mr. Gosselin said during the press briefing last week. “It will likely require several more years, in addition to what happened this past year, and more focused efforts on groundwater recharge and reduced demand.”
Water managers indicated this week the possibility of more El Niño conditions.
“It may not be wet, but it may not be as severely dry as some of the years we’ve seen recently,” Michael Anderson, the state climatologist with the Department of Water Resources, told media at the briefing.
Alex Tardy, a senior meteorologist at the National Oceanic and Atmospheric Administration in San Diego, said forecasters expect only a slight chance of above-average precipitation in the state this winter.
“There remains high uncertainty for the winter forecast,” Mr. Tardy said in an update on Oct. 2. “El Niño will affect the tropics and the jet streams, but we don’t know exactly where that lines up. There’s a lot of uncertainty.”
The state is also starting this water year with more flood-fighting materials than last year, according to Gary Lippner, deputy director of flood management and dam safety for the state.
California has about 2.4 million more sandbags and more “muscle wall,” a flood-control product that replaces sandbags and other solutions, Mr. Lippner said.
State water officials are also working with local officials and county agencies to protect flood systems and infrastructure, he said.
Gov. Gavin Newsom and the Legislature invested more than $430 million in the state’s most recent budget to support flood response and projects to protect communities from future flooding, according to the water department.
