‘No smoking gun.’ Algae blooms considered in mysterious death of family near Yosemite
Toxic algae blooms are among hazards being considered by investigators working to determine how a healthy Mariposa couple, their 1-year-old daughter, and dog mysteriously died along a Sierra National Forest trail.
Emergency responders this week initially treated it like a hazmat situation because of the strange circumstances – no visible body trauma – and concerns about potentially toxic gases from old mines in the area northeast of Mariposa and southwest of Yosemite National Park. The hazmat declaration was lifted Wednesday, Mariposa County Sheriff Jeremy Briese said.
“I don’t believe it’s connected to a mine,” Briese said of the deaths of Mariposa residents John Gerrish, Ellen Chung, their daughter, Miju, and family dog, Oski, described as looking similar to a golden retriever. “We don’t know the cause. … We won’t rest until we figure it out.”
Autopsies and toxicology tests will hopefully reveal more. They are planned for Thursday in Stanislaus County for the family of three (Mariposa County has a contract with the county for coroner services). Briese said Oski will also receive an autopsy through a partnership with Tulare County and UC Davis.
Their bodies were being airlifted out of Devil’s Gulch near the south fork of the Merced River on Wednesday afternoon.
The family was found dead Tuesday on the Savage-Lundy Trail in Devil’s Gulch near Hites Cove, a popular hiking destination. Briese said the family was located a couple miles from the south fork of the Merced River and about 1.5 miles from their vehicle, a gray truck, parked at a trailhead down Hites Cove Road past the Jerseydale Sierra National Forest station and community of Mariposa Pines.
That remote trailhead down a dirt road is accessed from the side closest to Highway 49. It’s different from another popular trailhead to the Hites Cove area along Highway 140 in the river canyon closer to Yosemite.
Family not near a mine, Mariposa County sheriff said
Briese said the family was found over three miles away from the only mine he’s aware of in that area, at the bottom of Hites Cove. He said crews have been searching around where they were found to make sure they aren’t missing some mines or other hazards.
“There’s a mining community,” Briese said of the area, “so there could be some that we don’t know about.”
One longtime, lifelong Mariposa County resident, Dave Givens, in the area Wednesday said there were over 300 mines in Mariposa County as of the 1950s, “and those are the registered mines.”
He was peering into Devil’s Gulch with binoculars, surveying fire damage from the 2018 Ferguson Fire and watching a California Highway Patrol helicopter hovering over where the family was found dead this week.
Givens wonders if one of many toxic gases from a mine could have killed them.
“Stay out of abandoned mines. ... There’s no maintenance,” Givens said as a general warning for hikers in that area. “Timbers rot, gasses collect. Not a good place.”
Sierra National Forest warns of toxic algae near Hites Cove
Briese said investigators are considering toxic algae blooms as a possible cause of death, but added, “We’re unsure.” He said the U.S. Forest Service had posted warnings about the algae at the trailhead of the trail where the family was found.
“And from what I’ve gathered, these algae blooms are due to the recent drought,” Briese said, “but I don’t know too much detail about the toxicity of them.”
Sierra National Forest posted a warning about the harmful blooms on its Facebook page July 13, stating water testing along the Merced River near Hites Cove showed a high concentration of algae bloom.
“The Sierra National Forest (SNF) would like to inform those visitors who like to enjoy this area of the Merced River and SNF, not to swim, wade or allow their pets to enjoy the water,” the post reads, in part.
Some species of algal mats can produce toxins, the agency continued, “and if present, can pose a risk to humans and pets.”
Ongoing investigation, and where they were found in Sierra
Briese said there’s no “smoking gun” clue indicating what happened, and that’s been frustrating.
“I’ve been here for 20 years and I’ve never seen a death-related case like this,” he said. “There’s no obvious indicator of how it occurred.”
Briese said his office is treating the investigation like a homicide “until we establish the cause,” adding, “we’re not going to rest” until that’s discovered.
He described the deceased couple as “very family oriented” and lovers of the outdoors.
“They’re smart, they know hiking and what type of gear you need or don’t need for the amount of time you’re out there, and it appears it was a day hike,” Briese said of their final hike together.
Deputies camped in Devil’s Gulch overnight Tuesday to keep the scene secure.
“We want to do everything we can to bring closure to the family,” Briese said, “to also identify the cause of what happened, and also to ensure the safety of our residents and people that enjoy that hiking area.”
The CHP helicopter hovering over the area lowered something into this location around 1:15 p.m. Wednesday, then flew away.
Briese said one rescuer was treated for a health issue related to the heat but was OK. Briese said around 3:15 p.m. Wednesday that he expected the family’s bodies to be extracted from Devil’s Gulch within that hour, then flown to the coroner’s office.
The Savage-Lundy Trail around where the family was found remained closed Wednesday.
A Mariposa County Sheriff’s Office official stopped media Wednesday afternoon along Hites Cove Road near the Hites Cove Helipad, past Apperson Mine Road, stating the scene ahead was closed. The remote location along a steep mountainside has expansive views into deep Devil’s Gulch canyon. Briese described the Savage-Lundy Trail there as a steep, established and popular trail.
A flock of wild turkeys and woodpeckers were among wildlife in the area Wednesday afternoon. The area is populated by pines, incense cedar and oaks – many killed in the 2018 Ferguson Fire.
Briese said the last major incident his office responded to in Devil’s Gulch was during that fire, when firefighter Braden Varney was found dead alongside his bulldozer at the bottom of a ravine.
“It’s tragic,” Briese said of the recent deaths. “It’s emotional for us as well as the community, and we’re going to do everything we can to ensure closure and safety of our community.”
This story was originally published August 18, 2021 at 9:18 PM.
