Risk of imminent failure of the Moccasin Dam has been reduced, but potential failure still exists. Flash flood warning remains in effect. Officials continue to monitor the situation closely. #CAwx pic.twitter.com/LD5JMfxjKk — NWS Sacramento (@NWSSacramento) March 23, 2018

Water levels have decreased at the Moccasin Dam and it is no longer in imminent danger of failing. However, a risk of potential failure still exists. The dam owner will continue to closely monitor the situation over the weekend. #cawx pic.twitter.com/QpB4aOskVK — NWS Sacramento (@NWSSacramento) March 23, 2018

**UPDATE** Moccasin Dam Appears Safe - SR120 Now Open

State Route 120 in Tuolumne County has reopened now that the Moccasin Dam has been determined to be sound and no longer in danger of failing. SR49 remains closed at Jct of SR120 due to undercut roadway. pic.twitter.com/ygsXgX0yJY — Caltrans District10 (@CaltransDist10) March 23, 2018

Imminent dam failure of Moccasin Reservoir Dam in Tuolumne County. Flood waters will be contained by Don Pedro Reservoir 1 mile downstream from Moccasin Dam. #CAwx pic.twitter.com/77kLWWL7C3 — NWS Sacramento (@NWSSacramento) March 22, 2018

TULOUMNE COUNTY, Calif. (KGO) -- A dam just west of Yosemite is holding steady. Earlier this afternoon, authorities warned it's likely it would fail. It did cause flooding in Tuolumne County.On Thursday afternoon, the California Fish and Wildlife Trout hatchery flooded in Tuolumne County. Workers there were evacuated. The water came rushing down from the Moccasin Reservoir Dam. The sheriff's department went into emergency mode because water authorities advised the dam would likely fail after heavy rain saturated the area. State Route 49 remains closed at State Route 120 because floodwaters washed out part of the road.Doctor Sukhmander Singh teaches Civil Engineering at Santa Clara University. He says this particular dam was built in 1930 and point out the majority of California's dams were built before 1970 and were made of compacted earth.But Singh says many of the construction records for the older dams don't exist so it's unknown how well the dirt was compacted."Sustained rainfall for long period bring runoff that means there's a possibility it may overflow, spillway may be overtaxed, overworked," explained Singh.The dam is stable for now.The San Francisco Public Utilities Commission is monitoring the situation and says the spillway is damaged.Everything will be inspected. The flood waters were contained by the Don Pedro Reservoir, a mile downstream.The reservoir is part of the Hetch Hetchy water system that provides millions of gallons of water to San Francisco, the Peninsula, and Santa Clara. Officials say our water supply in the Bay Area was not affected.