Flood — Tuolumne, California

2018-03-21 to 2018-03-22 · near Groveland Parsons Ar, Tuolumne, California

Event narrative

Extensive flooding in downtown Groveland, as floodwaters ran down the main street, Highway 120. Property was damage and water rescues for stranded residents. There was significant damage done to Groveland Community Hall and Mary Laveroni Community Park. Preliminary estimates from Tuolumne County are approximately $8 million for 16 damaged sites along county maintained roads. A very large portion of these damages are seen in the sinkhole at Ferretti Road and slides and embankment loss on Priest Coulterville Road.

Wider weather episode

Torrential rain from an atmospheric river with locally heavy convective showers brought flash flooding to portions of the northern Sierra and Motherlode foothills. The heaviest flooding was in Groveland, where 4-5 of rain fell, combining with 8-9 of rain in higher elevations upstream. There was also widespread damage in Tuolumne County to roads from debris flows, soil erosion, erosion of water conveyance systems, sewer systems that were inundated with excess water and debris. Roads damaged inluded state Highways 49 and 132. Moccasin Dam was damaged and came close to failure, with road closures. A tornado struck an amphitheater in Wheatland and caused minor damage. Heavy snow caused travel problems over Sierra highways.

View location on OpenStreetMap → (37.8500, -120.2000)

Source: NOAA Storm Events Database, event_id 747042. Narrative written by the NWS forecast office that issued the report.