Gabrielle Lurie/San Francisco Chronicle/Getty Images
- Officials were puzzled when a family of three and their dog were found dead on a hiking trail in California.
- Weeks later, extreme heat and probable dehydration were determined to be the cause of death.
- A survival expert told Insider this kind of tragedy "happens every year to unprepared adventurers."
After a family of three and their dog was found dead on a hiking trail in Northern California in August, officials were mystified over what killed them. More than two months later, extreme heat and dehydration were determined to be the cause of death.
According to one survival expert, such a tragedy is more common than you might think.
"Their deaths are truly a tragedy," Cat Bigney, a survival expert who has consulted for the likes of Bear Grylls and National Geographic, told Insider. "Unfortunately, it happens every year to unprepared adventurers."
On August 15, Jonathan Gerrish, Ellen Chung, their one-year-old daughter, Miju, and their dog, Oski, set out on a day hike in the Sierra National Forest, according to the Mariposa County Sheriff's Office. Estimated temperatures were 74 to 76 degrees Fahrenheit at the parking area where they left their car and set off on foot.
After hiking around 4.1 miles, the family reached an area where temperatures exceeded 100 degrees, before continuing on to a steep section of the trail that has no shade cover and constant sunlight. Officials said the family hiked for 2 miles on this section, where temperatures that day reached 107 to 109 degrees.
After friends reported them missing, their bodies were found on the trail, about 1.6 miles from their car, on August 17. Officials said the family had only one 85-ounce water container with them, which was empty.
Mariposa County Sheriff’s Office
On October 21, the sheriff's department said in a statement the family had died of "hyperthermia," or an overheated body, and "probable dehydration."
Sheriff Jeremy Briese noted that "heat-related deaths are extremely difficult to investigate" at the time.
Authorities said the family were frequent hikers, but Bigney said they most likely did not have enough water with them.
The container found with the family could only carry around 2.5 liters of water. Most adults require 2.7 to 3.7 liters on a typical day, according to the National Academies of Science, Engineering, and Medicine.
On a hike that involves moderate temperatures and moderate activity, it's recommended that adults drink 1 liter every 2 hours, according to experts at outdoor recreation retailer REI. In high heat or strenuous hiking, that could increase to 1 liter or more every hour.
"Although it is true that one can survive without water for 1-3 days, this depends on many factors including the temperature, level of exertion, and individual physiology," Bigney said.
Dehydration is a serious condition that many people underestimate. It can severely hinder a person's ability to physically and mentally function, according to Bigney.
"There can be a variety of symptoms from nausea, vomiting, cramps, headaches, confusion and others," she said.
In the case of this family, she said, the severity and onset of symptoms could vary. Adults tend to experience a gradual decline in their ability to function, but young children, who cope with physiological stress differently, might seem okay and then suddenly die.
Extreme heat is also more dangerous than many realize. From 1979 to 2018, more than 11,000 Americans died from heat-related causes, according to the CDC, with hundreds of deaths recorded every year.
While kids around the world live in extreme heat, Bigney said it's best to avoid bringing a child out in extreme temperatures that they are not acclimatized to, and especially if there is no access to proper hydration.
Bigney said that while what happened to this family is "common for those unprepared," their deaths "could likely have been prevented" with proper preparation.