The storm system exiting the Mother Lode on Thursday knocked down trees, including one of the oldest and largest in the Central Sierra, swelled creeks and rivers, tore up roads, broke pipes, flooded parks and libraries, blocked culverts, exposed leaky roofs, porches and at least one basement, and caused numerous power outages.
It also prompted the Tuolumne County Board of Supervisors to declare a local emergency for a handful of storm-damaged roads, including one in the Marshes Fire footprint, where heavy rains unleashed post-fire erosion that ripped out parts Marshes Flat Road near Moccasin.
Preliminary estimates for storm damage to Tuolumne County roads add up to about $2.3 million said Tracie Riggs, county Office of Emergency Services coordinator. The county is also waiting for damage estimates from Tuolumne Utilities District and Curtis Creek Elementary School, where a mudslide came down behind a portable building Wednesday and exposed a boulder.
The storm, which also dumped enough snow to bury ski resorts and place some ski patrol staff at Bear Valley in danger, left some Central Sierra reservoirs nearly full and prompted scientists to significantly downgrade the drought threat in Calaveras and Tuolumne counties.
Now residents along Highway 49 and up highways 4, 108 and 120 can expect a three-day window of clear weather to clean up from this past week of rain, mud and snow, and to get ready for the next bout of wet weather expected sometime next week, according to forecasts.
The past week’s six-day series of warm storms followed by cold storms, described as atmospheric rivers, brought more than 7 inches of rain to the Sonora area and as much as 13 inches of rain to watersheds that feed the Merced River, which crested above flood stage early Monday and prompted authorities to close Yosemite Valley.
The same storms hammered watersheds and communities up and down most of the west slope Sierra Nevada and unleashed rapid snowmelt runoff on the eastside Sierra, flooding U.S. 395 in places and putting parts of Reno under water.
Scientists took the past week into account as they updated a drought map for the Golden State released Thursday. It shows about half of Calaveras County, including foothill towns, remains in severe drought, while higher elevations are in moderate drought or abnormally dry. Most of Tuolumne County remains in severe drought, with the high north end of the county, including the Carson-Iceberg Wilderness, in moderate drought.
Three months ago, the entire Golden State was abnormally dry and 83.5 percent was in stages of drought. As of Thursday, 58 percent of California was in stages of drought.
Drizzle, sprinkles, showers and spells of pounding rains late Tuesday and early Wednesday combined to unleash tons of rock and loosen earth above and beneath Marshes Flat Road, also known as Kelly Grade, near the point of origin for the 1,000-acre Marshes Fire near Moccasin in September.
Marshes Flat Road traverses the edge of a ravine with a dropoff of about 250 feet with no guardrail, “and we have lost the fill that stabilizes the roadway,” Tanya Allen, supervising engineer for Tuolumne County, told county OES coordinator Tracie Riggs this week.
Photos Allen sent to Riggs and county District 4 Supervisor John Gray that show sharp-edged boulders perched on chopped-up pavement, streams of smaller rocks littered on what remains of the road, and jagged edges of old asphalt broken in places where aging white lines used to mark the road.
Engineering staff will trying to put together estimates that summarize costs for all roads damaged in the last storm, Allen said.
Other damaged roads in Tuolumne County include Italian Bar Road from the Columbia side, which has washed out in multiple locations, and is closed at the end of pavement leading to Lost Dutchman Mine Road, Italian Bar Road from the Twain Harte side, which has washed out near South Fork Road and is now one lane only for about 50 feet, and Kewin Mill Road, which washed out late Tuesday and early Wednesday when Five Mile Creek cut loose and severed a water main serving about 15 homes.
Flooding occurred in the basement of at least one property in downtown Sonora. Stephen Dietrich, owner of 74 and 76 S. Washington St., stepped knee-deep into water 3 to 4 feet deep as he ran a sump pump to drain the flooding through a hose to a storm drain on South Green Street.
“This is coming from an underground stream that’s coming from a wall on the uphill side,” Dietrich said, moving a flashlight beam to show the interior of the basement that dates to 1850. “It’s still flowing. You can hear it. I went to the city and reported it this morning.”
The basement flooding has not affected businesses on the ground floor, the On Main salon and Taqueria Sonora. An apartment tenant discovered the flooding on Wednesday, Dietrich said. There was also concern next door for flooding under Servente’s Saloon. A business owner there declined to be interviewed.
Elsewhere downtown, there was no flooding reported at Legend’s on South Washington or the Deluxe Barber Shop across the street on Theall.
“We have a water feature in the back of the shop in the basement, so we watch the water level there where it exits out of the building,” said Legends manager Katherine Rodriguez. “It’s high, but we’ve had no flooding so far.”
Gregory Petersen continued cutting a customer’s hair while he said he’s had no flooding issues this week at Deluxe Barber Shop on Theall Street.
“No basement flooding or anything like that, not that I’m aware of,” Petersen said. “But it wouldn’t surprise me if there was some place, because there are so many underground tunnels downtown.”
Tim Miller, Sonora city administrator and director of public works, said the basement flooding at 74 and 76 S. Washington was the only flooding issue he was aware of in downtown Sonora.
Citywide, weather-related incidents have been minor compared to damage reported in other communities, Miller said.
“We’ve had limited incidents through this storm,” Miller said. “We had a tree come down on
Shaws Flat Road over the weekend, which blocked street access and brought down some utility lines. We had three areas with some slides, most recently at Linoberg above the Save Mart, last night and today. We had a small slide on Forest Road, and another slide on Snell Street on the shoulder, out by Spring Hill.”
Earlier this week, Dragoon Gulch flooded and overtopped a trail area near the Alpine Lane access, Miller said. City staff closed the trail and hope to reopen it tomorrow.”
The city has no plans for an emergency declaration, Miller said. The city will have some additional costs for after-hours call-out time and overtime for public works crews.
Tuolumne Utilities District crews have finished repairs on a water main damaged when a culvert washed out earlier this week on Kewin Mill Road up in Cedar Ridge, said Tom Haglund, TUD’s general manager.
“Crews spent approximately 16 hours on the repair and reestablished water service to the affected portion of Cedar Ridge by about 6 p.m. on Wednesday,” Haglund said.
Advance preparations for the storm with attention to water treatment facilities and ditches helped the district weather the storm with all water treatment plants, ditches and the wastewater treatment facility performing as designed, Haglund said.
About seven trees came down along the ditch system, and they were removed, Haglund said.
As of Thursday, Lyons Reservoir was full and spilling, Lisa Westbrook with TUD said. Pinecrest reached capacity in the last few days.
“Now there is lots of snow in the watershed to ensure that Pinecrest and Lyons will be full likely well into June or even July,” Westbrook said.
According to a recent statewide snow content summary, the Central Sierra is now at 162 percent of normal as of Jan. 12, Westbrook said.
In Arnold, Calaveras County Water District crews worked overnight with contractor T&S Construction to stabilize a water transmission pipeline, exposed by storm runoff, that provides Arnold’s main water supply, Joel Metzger of CCWD said.
A metal I-beam was placed across a washed-out section of Blagen Road directly over the exposed pipeline, and heavy-duty straps were wrapped from the beam to the pipeline to provide stability, Metzger said.
Flooding on Big Trees Creek has receded to some degree since Wednesday, but the creek was still high Thursday and debris continued to wash toward the culvert under Blagen Road.
“A large pileup of sticks, logs and debris has clogged the upstream side of the culvert and water is rushing around both sides of the culvert and continues to undermine the soil under the roadway,” Metzger said in an update Thursday morning. “If the pile of clogged debris lets loose, CCWD is concerned that a large log could strike the pipeline and cause it to break.”
A temporary bridge was be placed across the compromised section of Blagen Road on Thursday, Metzger said, to allow CCWD workers to access its Ebbetts Pass area maintenance facility near Courtright-Emerson Ball Park. The bridge will be closed to the public
Earlier this week, flood waters in Big Trees Creek overwhelmed the culvert under Blagen Road in White Pines.
On the up side, Metzger said, “We’re mainly thrilled with all this rain and snow that is filling up the reservoirs we rely on.”
Yosemite road closures
As of Thursday afternoon, access into Yosemite National Park was restricted by rockfall on multiple roads, as well as heavy snow on Highway 120, also known as Big Oak Flat Road.
Highway 41, the Wawona Road, was the only way to get into Yosemite Valley, Scott Gediman of the National Park Service said.
“There is no access to Yosemite Valley via Highways 140 and 120,” Gediman said. “The only vehicular access to Yosemite Valley is along the Wawona Road.”
Highway 120 is closed at the Big Oak Flat Entrance due to heavy snowfall and dangerous driving conditions, Gediman said. Highway 140 is closed at the park boundary in El Portal.
Forecasts say . . .
A flood warning for Mother Lode foothill towns has been extended until 2:30 p.m. today as high waters in some creeks, streams and rivers continue to recede.
Forecasts for San Andreas, Murphys, Columbia and Jamestown show today is supposed to be sunny to mostly sunny, and the clear weather is supposed to last through Saturday and Sunday.
The next wet storm system could arrive in the Central Sierra mid-week next week.
Authorities urge residents to use the next few clear days to assess how they came through the past week, and to prepare for more potential wet weather.