Authorities identified the victim as 38-year-old Mara Flavia Araujo from Brazil.
ORIGINAL REPORT: Ironman participant drowns in Lake Woodlands during triathlon, according to officials
According to the Woodlands Fire Department, crews responded to Northshore Park around 7:30 a.m. on Saturday after a call about a lost swimmer in the lake.
Authorities said multiple boats were used in the search, including one with sonar detection equipment, which helps search the water when it has low visibility.
About 30 minutes later, officials said the sonar detected something that sank about 10 feet into the water, which was later confirmed to be Araujo.
Her body was taken out of the water, and she was pronounced dead, according to officials.
The sheriff's office said her official cause of death won't be ready until the autopsy is complete, but preliminary investigations indicated it was a drowning.
This is not the first Ironman athlete to die during the same competition.
Back in 2017, a 54-year-old man died while also swimming in Lake Woodlands.
On Saturday, first responders explained how swimming is not normally allowed in Lake Woodlands due to the "zero visibility" in the water, but exceptions are made for some special events, like the Ironman competition.
"When there are events in this lake, they get a special dispensation." Woodlands Fire Chief Palmer Buck. "Normally...we don't allow swimmers in Lake Woodlands due to the fact of the low visibility conditions and hidden structures, construction materials, and stuff underneath the water."
In a social media post, Ironman officials confirmed the victim was a participant in Saturday's triathlon, with the incident occurring during the swimming portion of the race.
ABC13 Houston reached out to Ironman officials, asking if there would be any changes to the swimming portion of this race, especially because the lake is known to have zero visibility.
ABC13 is still waiting to hear back.