The latest mid-winter storm, warmer than recent ones, brought warnings Wednesday about localized flooding in the Modesto area.
The National Weather Service issued a flood warning through 8 p.m. Thursday. Residents should watch out for pools of water on the roads, and for a “moderate” rise in river levels.
A 10-mile stretch of La Grange Road closed because of erosion at a bridge across a creek. It is off-limits to all but local traffic between Highway 132 in Stanislaus County and Highway 59 in Merced County.
A Merced County spokeswoman said some of the dirt has washed away from the substructure of the bridge, causing cracking of the bridge’s asphalt. Repairs were made to the same bridge last year.
There is no estimate on when the road will reopen.
The rain that started Tuesday night is predicted to strengthen Thursday and last through the weekend. The Sierra Nevada snowpack already was well above average, and the latest storm could bring mid-elevation rain that melts some of it.
The region’s large reservoirs have more water in them than normal for this time of year, but there is still room for runoff from the snowmelt. Don Pedro Reservoir on the Tuolumne River was at 78 percent of capacity Tuesday, the California Department of Water Resources reported. New Melones Reservoir on the Stanislaus River was at 80 percent.
This week’s storms could raise Don Pedro by 15 vertical feet, encroaching into the flood-control buffer mandated by the federal government, spokesman Brandon McMillan of the Turlock Irrigation District said. TID would have 15 days to restore the buffer through downstream releases, he said.
The Tuolumne and other rivers are not nearly as high as two years ago, when they ran close to their banks for several months. And 2017 was far less than the disastrous flooding of 1997.
The downtown gauge for the Modesto Irrigation District recorded 0.19 inches of rain from the latest storm as of 4 p.m. Wednesday. The city could get another half an inch to an inch Thursday night through Sunday night, the Weather Service said.
Wind speeds should pick up, with gusts up to 55 mph on Thursday. There is also a chance of isolated thunderstorms on Thursday.
Sunny skies should return Monday.
The Merced Sun Star contributed to this report.