“Takeaway message this morning is we’re about 24 hours or halfway through this 48-hour event,” he said. “Even though we’ve done well overnight, we haven’t had any significant amounts of flooding or impacts, we can’t let our guard down just yet.”

Imelda is the latest storm to hit a rain-weary region that has been battered by major storms and catastrophic flooding in recent years, from the so-called Tax Day floods of April 2016 to Hurricane Harvey two summers ago, which lingered over the city as a tropical storm. Heavy rain, high winds and tornadoes leveled entire neighborhoods, and some residents are still recovering.

Emma Wood, whose home was recently rebuilt after flooding during Harvey, had not yet unpacked in her new home by the time Imelda rolled in.

“I’m still looking at all of these boxes,” she said on Wednesday.

Ms. Wood, 81, had lived in her three-bedroom home in southern Houston for decades when it flooded as high as her shin in 2017. The house reeked of mildew afterward, she recalled, and floodwater left the floor warped, so she had to remember to step up and down when walking into her kitchen.

“It was dangerous for me,” she said.

When she had the chance to tear the house down and start anew, through a city recovery program, she jumped at the chance. She got the keys to her new house just last month.