2018 Winter Storm Event

On March 21-22, 2018, an atmospheric river moved into the State of California, coupled with convective showers that delivered 8-9 inches of rain in the higher elevations and 4-5 inches in the Groveland area. The combination of these two events delivered extreme amounts of precipitation and run off in a very short amount of time causing major flooding in the town of Groveland, as well County-wide damages of soil erosion under roads and culverts, erosion of water conveyance systems, sewer systems that were inundated with excess water, debris and silt.

​This ultimately resulted in multiple road failures and closures, and unsafe road conditions for ingress and egress for residents and emergency responders.​​​​The Tuolumne County Board of Supervisors proclaimed a Local State of Emergency that was ratified on March 28, 2018. This proclamation requested assistance from State and Federal Agencies for anticipated damages from the Storm Events.​​ In April 2018, representatives from Cal OES and FEMA were escorted to known damaged sites to conduct preliminary assessments.

​Below is a preliminary list of damages caused by this storm event. This is in addition to damages sustained by multiple residences and businesses throughout Tuolumne County. You can view rainfall totals from March 20-22 at https://www.cnrfc.noaa.gov/precipMarch2018.php.

Road Closures
  • Marshes Flat Road (From Hwy 49)                Closed
  • Marshes Flat Road (From Lake Don Pedro)  1 Lane open at 1st and 2nd Creek
  • Priest Coulterville Road                                  1 Lane open at various sites
  • Ferretti Road                                                   Closed at PML Drive to Mueller Drive
  • 5 Mile Creek Road                                          Closed from Big Hill Rd Direction , Yankee Hill direction remains open
County-Maintained Roads sustaining significant Damage
  • 5 Mile Creek Road
  • Black Road
  • Christy May Rd
  • Deer Flat Road
  • Ferretti Road
  • Las Palmas Way
  • Marshes Flat Road
  • Merrell Road
  • Old Highway 120
  • Priest Coulterville Road
  • Zarzamora Road
Key US Forest Service Road Failures (as of May 2018)
  • Crocker Ridge Road (2S30)
  • Buchanan Road (1N01)
  • Beardsley Day Use Road (4N29)
  • Hell's Half Acre Road (5N29)
  • Donnell's Dam Road (5N09X)
  • Sourgrass Road (5N14)
Other Infrastructure- Public Agencies
  • Mocassin Dam and Fish Hatchery
  • Groveland Community Hall
  • Mary Laveroni Community Park
  • Belleview Elementary School
  • Big Oak Flat School District
  • Lake Don Pedro CSD
  • Groveland CSD
  • Tuolumne Utilities District