Authorities said 39-year-old Jason Clark of Magnolia died at the scene after the crash, which happened off the shore near North Diamondhead Road. Clark's wife, Sara, is in critical condition as of late Wednesday afternoon, according to a spokesperson at Conroe Regional Medical Center.
Their daughter called 911 after the accident and guided first responders to the scene of the accident with the light from her cell phone.
"She was able to talk us to her," said Montgomery County Precinct 1 Constable Lt. Tim Cade. "Before we arrived on the scene, we knew where we were going, we knew what we were coming up on, and we knew what we had to do before ever getting there."
"This is from a 10-year-old and that, in my book, that's a hero," he added.
All three members of the Clark family were wearing life jackets at the time of the accident, according to investigators.
VIDEO: Authorities discuss fatal boating accident on Lake Conroe
The other boat, which had two men aboard, capsized. The men were thrown into the water but were wearing life jackets and are okay.
It's not clear which boat was moving and which was still in the water. The Texas Parks and Wildlife Department will lead the crash reconstruction beginning Thursday morning.
Alcohol was not a factor in the crash.
Investigators said both boats had the proper marker lights illuminated at the time. Officials added while the boats were lit in accordance with law, the amount of lights on the lake makes it hard to tell between boats and homes.
"It's very difficult to see moving watercraft across that lake because across the horizon, especially in a busy creek like that, you see all kinds of other lighting," Mack said.