Tuolumne County feels brunt of storm as roads wash away; Modesto relatively unscathed
A storm that moved through the area on Thursday flooded homes, washed out roads and threatened a dam in the foothills, though the Modesto area came through mostly unscathed.
Tuolumne County took the brunt of Thursday's storm, with several roads washed out near Jamestown, Sonora, Groveland and Coulterville.
The National Weather Service issued a flash flood warning and said the Moccasin Dam was in "imminent" danger of failing, though officials later reduced that threat to "potential."
A section of Highway 132 washed away east of Coulterville, while videos showed water rushing through downtown Groveland and over several streets in Sonora and Jamestown.
Late Thursday afternoon, the Tuolumne County Sheriff's office said it was working to set up shelters for people who could not get to their homes. Mariposa County, which had major flooding, as well, opened a shelter at Mariposa Elementary School.
Sheriff's officials in Tuolumne County said their swift water rescue team had been helping to reach a couple stranded on top of a chicken coop. "Their home and vehicles are under water," the sheriff's department said in a Tweet. Neighbors helped the couple reach safety.
Should the Moccasin dam fail, any water released would be handled by the Don Pedro Reservoir, located about a mile downstream.
The Turlock Irrigation District said if the dam fails, it would have a very small impact on Don Pedro's storage capacity and the flows from the reservoir.
TID spokesman Calvin Curtin said that is because Moccasin is such a small facility and it would raise the level of Don Pedro by less than one half of one foot. But the TID is looking at the potential impacts of debris, including logs, mud and rocks, that could enter Don Pedro if Moccasin failed and what steps it could take to mitigate that.
The state Department of Fish and Wildlife evacuated a hatchery it operates there; officials said everyone got out safely. The community of Moccasin, located above the reservoir, is safe, officials said.
The Sonora-area California Highway Patrol and other emergency responders spent the day responding to water and mud across roadways, power failures, traffic collisions and flooding.
Shortly before noon, nearly 225 students were being evacuated from Gold Rush Charter School on Hidden Valley Road in Sonora.
Tuolumne County Sheriff's Office Lt. Neil Evans said the creek next to the school (once named Sylvan Creek School) is rising and caused road access to the school to be cut off. No classrooms were flooding, he said about 12:15 p.m., but students were being sent home as a precaution.
CalFire has set up an incident command center at the school, Evans said, and buses were on the way to get children out who didn't have parents on the way. "A power line is down on one of the main roads to get there," he said, "but other routes are open."
Just after 11 a.m., there was a report of floodwater coming into Sonora's Pine Tree Restaurant, 196012 Hess Ave, from beneath the doors.
Caltrans reported in the late morning that in eastern Stanislaus County, State Route 132 was closed in both directions from Rushing Road to La Grange because water and debris were flowing across the highway throughout the area. Drivers were told to find alternate routes.
The TID sent out a notice that beginning Friday, flows from Don Pedro to the Tuolumne River below La Grange Dam will be gradually increased until they reach a maximum of 3,500 cubic feet per second. The flows will be reduced to 2,600 cfs early next week.
As a result, the Tuolumne River will rise over the course of the next two days by about five feet when measured at Ninth Street in Modesto.
"This level is below monitor stage and is not a cause for concern," TID said. "According to our forecasts, the river should reach approximately 45 feet in elevation, which is 10 feet below flood stage.
"Releases like these are a part of normal operations on the river and should not be cause for alarm. However, conditions can change and TID will continue to monitor the situation and provide updates as appropriate. As always, we recommend using extreme caution near any river as the water is cold, fast moving and can contain debris."
In the meantime, Modesto received only 0.13 inches of rain on Thursday, according to the Modesto Irrigation District.
The storm is expected to clear out Friday, but there is more on tap this weekend, according to the National Weather Service.
Bee Staff Writer Kevin Valine contributed to this report.
This story was originally published March 22, 2018 at 12:35 PM with the headline "Tuolumne County feels brunt of storm as roads wash away; Modesto relatively unscathed."