(CNN) - A woman who jumped in to help save a boy whose three siblings drowned in Texas described the child's struggle to stay afloat after they were overcome by waves.
The three siblings drowned Thursday night at Sylvan Beach Park in La Porte, officials said. They were ages 11, 13 and 7, Chambers County Sheriff Brian Hawthorne said in a statement.
A fourth child, who's 10 years old, was pulled from the water and survived, Harris County Sheriff Ed Gonzalez. said.
Veronika Alvarez, 23, said she was at the scene when her dog started barking. She saw the parents trying to grab a child and jumped into the water to help, she told CNN affiliate KTRK/ABC.
"I just jumped in because no one was responding. Everybody was quick to grab their phones, but I was like, it's not important. What's important is the people who are drowning,"she told the affiliate.
She said the boy was in shock, wasn't swimming and was going down, and added that she kept telling herself to "keep him above water, keep him above water."
Alvarez said she was taken to a hospital, where she was treated after inhaling "small amounts of water" into her lungs. The boy was treated at the scene and released.
The family has not been identified, but Gonzalez said he believes they recently moved to the Houston area from another state
Sylvan Beach Park is in La Porte,a city east of Houston on Galveston Bay.
Search took four hours
Police received a call to report the drowning around 7:15 p.m. and arrived on the scene within minutes, Gonzalez told OnScene.TV.
Dozens of emergency responders, including local police and fire departments, and units from the Coast Guard and Port of Houston, were on the scene with drones, helicopters, trucks and ambulances. Beachgoers, some still wearing swimsuits and draped in towels, watched from the shore.
"Things happened really quickly," Gonzalez said. "A lot of people were out here, the kids were playing, mom and dad were here as well." He added that the parents "are very distraught. There's no way to make it any softer."
The total search time for all three siblings was about four hours, he said. The reason the children drowned is still unclear. They may have been swimming beyond a water safety buoy and encountered strong tides and rip currents, Gonzalez said.
Police are looking into whether a large boat went by, creating rough waters, he added.
CNN's Susan Scutti contributed to this report.
The-CNN-Wire ™ & © 2019 Cable News Network, Inc., a Time Warner Company. All rights reserved.