A Northern California family who were found dead in a remote hiking area are believed to have been killed by hyperthermia and probable dehydration, the Mariposa County sheriff said Thursday.
Sheriff Jeremy Briese held a news conference to discuss the investigation into the mysterious deaths of John Gerrish, Ellen Chung, their 1-year-old daughter and their dog.
The family had gone hiking on a trail near the Merced River in the Sierra National Forest and were found dead Aug. 17 after a family friend reported them missing the previous night.
They were found about 1½ miles from their car, apparently having completed about 6 miles of their intended route on the Hites Cove and Savage-Lundy trails. They had one 85-ounce water bladder with them; it was empty, Briese said.
Much of the route, inside the Ferguson Fire footprint, has little shade, and temperatures on Aug. 15 reached 109 in the area. The last stretch, on the Savage-Lundy Trail, is on a steep incline, rising from about 1,800 feet elevation to 3,900 feet in 3½ miles. With a south/southeastern exposure, it was in constant sun. (Click here for a map of the route, with temperature notations.)
Hyperthermia is abnormally high body temperature caused by the failure of heat-regulating mechanisms.
Mariposa County sheriff’s investigators had already ruled out several potential causes: a gun or any other weapon, a lightning strike, carbon monoxide, carbon dioxide, cyanide, illegal drugs, alcohol or suicide.
The sheriff’s office also had said previously that “extreme heat” had been ruled out, but Briese said Thursday that the investigators are now convinced that the finding of hyperthermia and dehydration is correct for the couple and their daughter, Aurelia Miju. They said the cause of death of the dog — Oski, an 8-year-old akita/Australian shepherd mix — remains undetermined, but that it was likely also heat-related.
One early theory centered on high levels of toxic algae detected in the Merced River. Briese said water samples taken in the area found the algae but that toxicology tests did not indicate that any of the family members had ingested it. Residual water from the hydration bladder was also tested, and it was found to be clean, the sheriff said.
The deaths led the Bureau of Land Management to close campgrounds and recreation areas along 28 miles of the river, between the towns of Briceburg and Bagby, when water samples downstream from where the family died showed high levels of the toxic algae.
Gerrish was 45 and Chung was 30. They had moved last year from the Bay Area to Mariposa County.
The couple were described by friends as experienced hikers. Briese suggested that, as relative newcomers to the area, they may not have been aware of the steepness of the terrain and how quickly temperatures could rise. When they began hiking, he said, the temperature was in the mid-70s; when they had gone barely 2 miles, it was already above 90.
They were reported missing on the night of Aug. 16. Their baby sitter had found them gone when she showed up at their house that morning — a Monday — and had started contacting their friends to see if anybody knew their whereabouts.
Gerrish was carrying a phone during the hike. It has been sent to the FBI to determine if it can provide any insight into the family’s last hours.
— The Associated Press contributed to this report.
