Updated at 12:15 p.m. Aug. 7: Revised to include the woman's cause of death.

A woman died after a hike June 18 in Big Bend National Park, where temperatures soared above 100 degrees, officials said.

Cathlyn Weir, 46, of Cedar Hill, started showing signs of heat distress and dehydration around mid morning while she and her partner hiked the Dog Canyon trail, the park said in a prepared statement.

Her hiking partner went for help about 2:30 p.m. Officials found the woman's body two hours later.

Her cause of death was determined to be environmental hyperthermia, or heat illnesses, officials said.

Temperatures in the shade in that part of the park were reported to be 110 degrees that day.

Weir is the first person to die in the park this year. Last year, four people died in Big Bend: one fell of a cliff, another had an allergic reaction, and two more had heart attacks, park spokeswoman Jennette Jurado told the San Antonio Express-News.

"Big Bend National Park's staff wishes to send sincere condolences to the friends and family of the deceased, and reminds all visitors to take precautions when visiting the park during periods of intense heat and severe conditions," the park said in a statement.

Temperatures in the park at low and mid elevations can be above 100 degrees this time of the year, with heat indexes sending them above 115, according to an alert on the park's website.

A week before Weir died, on a day where temperatures reached 111 degrees, there were two search and rescues and four heat-related illnesses, the park said on Facebook.

The park encourages people to finish hikes before 11 a.m., drink at least a gallon of water per day, bring snacks and dress for the weather, including lightweight long-sleeved clothing and wide-brimmed hats.

A Keller Central High School student died June 12 after collapsing during a Boy Scout backpacking trip in West Texas.

John Reid Comita, 15, was hiking at the Buffalo Trail Scout Ranch near Fort Davis. Heat stroke is suspected in his death.

Staff writer Nicole Cobler contributed to this report.