When the rainfall turned torrential late Saturday night, and water began pouring into his living room, KeRon Hooey sloshed down the block to the highest ground in the neighborhood: his neighbor's two-story house.
He and 10 others, including two elderly neighbors, spent the night on the second floor, watching the waters rising out of the nearby Buffalo Bayou and spreading across their quiet subdivision, Wood Shadows II.
All night, Hooey dialed emergency numbers – 911, 311, the Coast Guard, local police stations – only to find wait times of more than two hours, or lines so busy that his calls were dropped. So he turned to Twitter.
"Entire Wood Shadows II neighborhood is under water," Hooey wrote in a Tweet posted at 4:23 a.m. Then he shared his address.
As Tropical Storm Harvey drenched Houston, hundreds of residents trapped in rising waters inside their homes encountered long waits and dropped calls on the region's 911 lines.
After officials reported that emergency lines were "at capacity," residents like Hooey turned to Twitter and Facebook, breaking with typical Internet privacy standards to share their home addresses and phone numbers in hopes of a quicker rescue.
One woman begged someone to help her aging parents, trapped in waist-high water in the Meyerland neighborhood. Talk-show host Montel Williams posted a video on Facebook, asking someone with a boat to rescue a colleague with cerebral palsy. Other users reported relatives with heart conditions, and families with children who could not swim.
Just after 1 a.m., a woman in the Ellington neighborhood said on Twitter that she had two children with her, and "The water is swallowing us up. Please send help. 911 is not responding!!!!!!"
One woman in southeast Houston shared a photo of murky yellow water covering her home, saying: "I really need rescue, and no numbers are working."
A sort of volunteer social media brigade began to respond, urging stranded Houston residents to leave their attics and head for the roof. Others tried what they called a "signal boost," retweeting posts and tagging emergency officials in an effort to speed the rescue process.
On Sunday night, Houston Mayor Sylvester Turner said 911 operators had received 56,000 calls in less than 24 hours. Police and fire departments had received nearly 6,000 calls for rescues and rescued more than 1,000 people, he said.
"If you're stranded in your vehicle, but you are in a safe place, or a dry place, let's give preference to those who are in a situation in their home where water is rising very quickly," Turner said at a televised news conference earlier Sunday. "I ask that you continue to call. We are manning 911. But a lot of calls have come in."
He urged residents who were not in life-threatening situations to stop calling emergency lines.
Harris County Sheriff Ed Gonzalez said 911 dispatchers had missed some calls "due to volume," and were trying to call those numbers back.
Officials stressed that callers should stay on the line and wait, instead of hanging up and calling back. Those seeking immediate help can contact the U.S. Coast Guard, officials said.
Emergency responders also sent out pleas on social media to residents who own boats and high-water vehicles, asking them to contact fire officials to help with rescues in flooded neighborhoods.
As the sun rose, Hooey and his neighbors began trying to get the attention of passing helicopters, waving T-shirts and flags, and blinking their phone flashlights on and off.
At 10:30 a.m., Coast Guard officials picked up Hooey's two elderly neighbors and the women in the group, wading through waist-high water to load a walker and a wheelchair in the boat.
The Coast Guard didn't return for the rest of the group, Hooey said, and they hitched a ride on a resident's boat, gliding down what had once been Centerwood Drive.
"Oh my God, this is just a horrific experience," Hooey remembered thinking as he saw roofs, cars and lamp posts poking out of the water. Then he wondered why Houston officials had not told his neighborhood to evacuate — because he would have, he said.
"We were told to stay inside and stay safe, and there was no plan at all," Hooey said. "Houston has to do better."
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5:40 p.m.: This article has been updated with figures and comments from the mayor's news conference.
2:45 p.m.: This article has been updated with description from a resident and other details.