Wednesday’s atmospheric river storm brought painfully slow morning commutes across Northern California, some flooding in common trouble spots in Sacramento and a rare layer of thick snow in the northern Sacramento Valley.
But otherwise the state’s network of flood-control dams and levees appeared to handle the deluge without major problems.
The National Weather Service issued a flood warning Wednesday morning for the Sacramento Valley, and it was expected to remain in place until 8 p.m. as heavy and moderate rainfall was forecast to continue through the evening.
As of midday, the rivers and streams around Sacramento were generally behaving themselves, although Discovery Park near downtown Sacramento was expected to flood Wednesday afternoon. Flooding routinely happens this time of year when officials release water into the American River from Folsom Dam to make space in the lake to catch mountain storm runoff.
Park rangers had been making the rounds in advance of the Folsom releases, urging more than 150 people camping in Discovery Park to find higher ground, said Kim Nava, a spokeswoman for the park.
Howe Avenue and Watt Avenue river access to the American River Parkway were closed Wednesday and will remain that way until the American River recedes.
Elsewhere in Sacramento County, the usual flood-prone areas around Arcade Creek, the Cosumnes River and in Rio Linda were being closely watched. County officials also had opened self-serve sandbag stations, but major flooding wasn’t reported by midday.
“It’s routine right now,” said Matt Robinson, a spokesman for Sacramento County’s Department of Water Resources. “If we have another storm that comes behind it, things could change.”
By midday, an inch of rain had fallen at Sacramento Executive Airport over the past 24 hours, with similar amounts reported in Rio Linda and Auburn.
The Sacramento area has already gotten nearly 2 inches of rain this month. The normal for all of February is 3.69 inches.
Further north, a colder than normal storm brought up to a foot of snow in some lowland areas of Shasta County, leading to power outages as trees toppled, local residents reported.
“It is a mess,” said Nadine Bailey, an Anderson resident whose Facebook page featured a picture of downed limbs in her driveway and about 8 inches of snow on the ground. The snow was so thick Wednesday state highway officials closed northbound Interstate 5 north of Redding to the Oregon border. The freeway was expected to stay closed for much of the afternoon.
In Sacramento, the rainy roads made things a mess for commuters Wednesday morning, with numerous spin outs and accidents clogging lanes.
There may not be much of an improvement Thursday. The National Weather Service says Thursday in Sacramento will bring 1/4- to 1/2-inch of rain to the city.
Starting Thursday afternoon, commuters heading to and from Sacramento from Davis or Woodland will be driving over the flooded Yolo Bypass, the century-old engineered flood plain west of Sacramento that keeps the city from flooding when the Sacramento River gets too high.
Beyond the Sacramento metro area, the Russian River could cause problems in Guerneville and the Napa River was likely to hit flood stage in St. Helena, said Alan Haynes of the federal California Nevada River Forecast Center.
The “burn scar” area around Paradise, site of last November’s Camp Fire, could see some flooding if the rain intensifies, Haynes said.
Managing the storm has been made easier for California’s flood managers because most of the state’s major reservoirs still have ample room to accommodate storm runoff, Haynes said.
Shasta Lake — the state’s largest reservoir — was 69 percent full Wednesday. The second largest, Lake Oroville, which is being kept deliberately low this winter because repairs to the dam’s fractured spillways are still not finished, was 45 percent full, California Department of Water Resources figures show.
Folsom Lake is 62 percent full. On Tuesday, the dams’ federal managers opened its more than $900 million auxiliary spillway for the first time to make room in the lake.
There’s not another release from the new structure scheduled yet this week, but dam managers expect to use the new spillway often in the months and years ahead to help manage Folsom’s levels, said Erin Curtis, a spokeswoman for the U.S. Bureau of Reclamation, which manages the dam.
Meanwhile, Wednesday’s storm bumped the index of precipitation in the northern Sierra Nevada to 106 percent of historical average, according to state figures. The statewide Sierra snowpack is 30 percent above normal.
All told, the state’s water outlook is on track to be at or a little above average, said Michael Anderson, a climatologist with the state Department of Water Resources.