A newly obtained report from the investigation into the August deaths of two former Bay Area residents, their infant and their dog suggests a likely sequence of events. And it's beyond tragic.

31-year-old Ellen Chung and 45-year-old Jonathan Gerrish relocated from San Francisco during the pandemic to the more rural Mariposa County, where they had already purchased several rental properties from which they were making income through Airbnb. Both outdoorsy people, but with perhaps a dearth of real familiarity with the terrain nearby, the couple made a fateful decision on the morning of August 15 to go on a hike in the area of Hites Cove and Devil's Gulch. They were later found dead along a hiking trail, and it would be two months before investigators would publish a conclusive cause of death: hyperthermia (overheating) and probably dehydration.


The Chronicle has now obtained 77 pages of investigative reports from the case, and the paper reports new details about where and how Chun, Gerrish, their baby, and their pet were found on the Savage-Lundy Trail. As we learned earlier, they were found 1.6 miles from the trailhead, having completed four fifths of an ambitious 7.5-mile loop that locals and U.S. Forest Service officials would have advised against in the summer months.

No one else was likely out on the trails and no one reported seeing the couple and their child that day after one witness reported seeing their truck pass by in the morning, heading to the Hites Cove trailhead.

It's believed that they began their hike before 8 a.m., at the point marked 1 on the map below — the trailhead is at an elevation of 3900 feet, and the temperature at that hour was around 75 degrees. By the time they reached point 3 on the map, they would have descended to 1800 feet, and the temperature would have been around 100 degrees.

That was at the foot of the Savage-Lundy Trail, a harrowing set of switchbacks that, after 3 miles and an elevation gain of over 2000 feet, would bring them back up to the trailhead where they'd parked their car. A U.S. Forest Service brochure says that this is the most difficult of all the trails in the area — and the website Yosemite Hikes suggests that the ideal time for hiking in this area is March to May, and, "By the end of May, the grass and flowers are dying and it's getting much too hot anyway."

Chung and Gerrish would only make it halfway through this section, and investigators believe that the infant was likely to have succumbed to the heat first. Also, the couple's dog, Oski, was an Australian shepherd-Akita mix, and had a heavy coat meant for wintry weather, so the dog also likely would have been in major distress. Investigators also noted that there is little to no tree cover along these trails after the 2018 Ferguson Fire, so there would have been no place to seek shade.

By the time the couple likely collapsed from the heat, it was as hot as 109 degrees in this area. And without any shade, the ground would have been sizzling hot and painful to even sit on.

Ellen Chung, Jonathan Gerrish, their child Miju, and their dog Oski.

Chung was found just a short distance ahead of Gerrish — and only 13 feet higher in elevation, near the trail. Investigators did not initially find her, but followed some disturbed soil and found her just off the trail.

It's believed Gerrish may have sat down and attempted to cool down with the infant in distress while Chung may have tried to go ahead to seek help — or perhaps everyone was delirious at this point. As we learned in the case of another tragedy, when Berkeley runner Philip Kreycik also succumbed in 100+-degree heat near Pleasanton a month earlier, heat stroke can lead to irrational behavior. Hyperthermia shuts the brain down first, followed by other organs. Kreycik was found far off the trail he had been on, perhaps because he was seeking shade under a lone tree in the area.

A Forest Service volunteer who was familiar with the loop Chung and Gerrish took told investigators that he would typically wait until after sundown to do the final leg. And he said they would have needed 320 ounces of water between them, and 16 ounces each for the baby and dog, but Gerrish only carried a water bladder with 84 ounces in total. It had only a few drops in it when they were found, and investigators tested the water in an effort to find the cause of death.

In the end, even some toxic algae in the nearby Merced River would not have been enough to kill the dog — who apparently did ingest some in an effort to cool down and hydrate.

It all adds up to a tragic and cautionary trail, especially for "city folk," as a local construction manager reportedly referred to Chung and Gerrish. Lots of places in California, even in the Bay Area, are not hospitable for summer hiking.

Related: Cause of Death Finally Revealed In Case of Former SF Couple and Infant On Sierra Hike

Top image: A view near the Hites Cove trailhead taken in the more hospitable spring months.