Update: Evacuation Advisories Below Twain Harte Lake Dam Lifted
Update at 8:15 a.m.: All evacuation advisories were lifted last night after the California Department of Safety of Dams determined the Twain Harte Lake Dam to be “structurally sound and clear for continued use.” Tuolumne County sheriff spokesperson Nicco Sandelin gives this latest update on the cracks found in the granite rocks near the dam, “Twain Harte Lake Association will continue with draining water from the lake and monitoring the dam.” There is currently no word on the next steps regarding fixing the cracks.
Update at 7 p.m. Friday (Dec. 23): Evacuation advisories have been lifted near the Twain Harte Lake Dam. They were originally issued after cracks were found in the granite rock near the dam. OES Director Dore Bietz updates that a thorough inspection found that “the dam appears structurally sound.”
Further details regarding the cracks near the dam are below.
Update at 3:25 p.m.: Tuolumne County OES just released this update with the latest information on the Twain Harte Lake Dam incident:
“Tuolumne County OES was updated this afternoon that there are cracks in the granite near the Twain Harte Lake Dam and not the dam itself. Emergency responders are on scene to evaluate and determine potential integrity issues. An Evacuation Advisory has been extended to include residences located from Good Shepherd Dr to the Sullivan Creek Bridge located on Phoenix Lake Rd. Again, this is an evacuation advisory for homes along Sullivan Creek due to potential integrity issues with the dam. Multi agencies are on-site evaluating. Twain Harte Lake is slowly releasing water to mitigate impacts and allow for inspection. Please avoid the area.” There are advisory evacuations also on Lucky Strike Trail in Upper Crystal Falls.
Earlier Sheriff’s spokesperson Nicco Sandelin noted that the draining of the lake will cause rising waters downstream and for residents in those areas not to be alarmed. Twain Harte is in Tuolumne County District 2, that is Supervisor Ryan Campbell’s district. He surveyed the dam this afternoon and shot the video in the image box that shows how Sulivan Creek is fairing.
Sandelin also had this update regarding whether there was an actual explosion, stating, “There was no explosion, but likely the sound that was being reported was a cracking of a rock where the dam is located.” He added, “There were no signs of any explosive devices or explosions in the area.”
An update will be provided as soon as new information comes into the newsroom. Further details on the situation and possible repairs are below.
Update at 2:15 p.m.: There is new information being released regarding exactly where the crack is located at the Twain Harte Lake Dam. Office of Emergency Services Director Dore Bietz tells Clarke Broadcasting, “The cracks are in granite next to dam, not dam itself.”
In an earlier statement released by OES, it detailed that emergency personnel are still working to determine the full impact of the damage to the dam and surrounding infrastructure and asked the public to stay out of the area.
Update at 1:45 p.m.: Tuolumne Sheriff’s Office updates that there is an additional evacuation advisory due to the cracks found in the Twain Harte Lake Dam. It is in the areas east of the Sullivan Creek Bridge along the creek. An earlier advisory went out this morning for the areas of Good Shepherd Drive and Lucky Strike Trail in Upper Crystal Falls. This means that residents in those areas should be prepared to leave if notified by sheriff’s officials. It is not an evacuation order.
The cracks were found after 911 got several calls reporting a sound of an explosion near the dam. Sheriff’s spokesperson Nicco Sandelin updated Clarke Broadcasting regarding whether there was an actual explosion, stating, “There was no explosion, but likely the sound that was being reported was a cracking of a rock where the dam is located.” He added, “There were no signs of any explosive devices or explosions in the area.”
What caused the cracks has not yet been determined, according to Sandelin. Back in August of 2014, there was a similar situation at the dam. A leak was found with water coming out of a crack. The lake was drained to about 10 feet so repairs could be made, as reported here. Sandelin noted that they are slowly releasing water from the lake at this time. He added, “It’s still preliminary at this point we are still looking at all the options.”
Sandelin also advises that residents near the dam may notice rising waters downstream but that is due to the draining taking place.
Update at 1:10 p.m.: Tuolumne County Sheriff’s spokesperson Nicco Sandelin updates Clarke Broadcasting about the latest steps being taken regarding the cracks that were found in the dam. He advised, “Water will begin to get released from the Twain Harte Lake which will create a rise in water levels downstream.
Please remain calm.”
We will pass along any further updates as soon as they are released.
Update at 12:50 p.m.: Tuolumne County Sheriff’s Deputies, firefighters, OES officials, and others remain at Twain Harte Lake Dam after a loud explosion was heard and then cracks were found in the dam. Here is the latest information on the situation provided by OES:
Tuolumne County OES was notified this morning that the Twain Harte Lake Dam began leaking due to cracks. Emergency responders are on scene to evaluate and determine
potential. An evacuation advisory is being sent out to those below the dam in the Good
Shepard Drive and Lucky Strike Trail area below as a precaution. As things change, we will
evaluate and notify the public.
Emergency personnel are still working to determine the full impact of the damage at Twain
Harte Lake to the dam itself and surrounding infrastructure. For overall safety, the public is
asked to avoid Twain Harte Lake area where first responders are staging.
Twain Harte Lake
• 20-25 feet deep
• Approximate 142 acre-feet capacity
• Owner: Twain Harte Lake Association
The following emergency agencies are coordinating response:
• Tuolumne County Office of Emergency Services
• Tuolumne County Sheriff’s Office
• Twain Harte Community Services District
• Twain Harte Fire
• Tuolumne Utilities District
• Cal Fire
• California Office of Emergency Services
• California Division of Dam Safety
There was a similar incident back in August of 2014 when a loud boom was reported by residents near the dam. At that time, a crack was found and water was leaking from it. The lake had to be drained to make repairs, as detailed here.
Original post at 12:23 p.m.: Twain Harte, CA – Reports of a loud “explosion” have Tuolumne County Sheriff’s officials, firefighters and Office of Emergency Services (OES) investigating the Twain Harte Lake Dam – and cracks have been found.
The sheriff’s office has issued an evacuation advisory for the areas of Good Shepherd Drive and Lucky Strike Trail in Upper Crystal Falls. This means that residents in that area should be prepared to leave if notified by sheriff’s officials. It is not an evacuation order. An update will be provided as soon as new information comes into the newsroom.