Searchers today found the body of 39-year-old Eddison Hermond, a National Guardsman and Air Force veteran, in the Patapsco River, just across the Baltimore County line, the Howard County Police Department said.
Hermond, of Severn, Maryland, was last seen at about 5:20 p.m. Sunday.
When the flash flooding rushed in, pet food store owner Kate Bowman escaped with her cat from the window of her shop and was in water above her waist when she saw Hermond, The Baltimore Sun reported.
Hermond was at a restaurant with Joseph Lopez, his friend from the Air Force.
“It happened so fast," Lopez told ABC News of the flooding. “The main street became a river in less than 20 minutes."
“I could barely see anything and I could barely hear anything” because of the rushing waters, Bowman, 41, told The Baltimore Sun through tears.
Hermond "stepped over the ledge to try to get to me, and he was washed away," she told the newspaper.
Bowman made it to safety but Hermond was swept away.
“He was trying to save me,” Bowman told The Baltimore Sun. “He’s a hero.”
Hermond had been a member of the Maryland Army National Guard since 2009, a National Guard spokesman said. He had joined the Air Force in 1996 and served on active duty for 10 years. He took a short break in service before joining the Guard three years later.
"We want to thank everyone for the outpouring of love and support," Hermond’s aunt, Deborah Nina Cooper, told ABC News today.
"The family is very grateful to all the supportive messages," she said, adding that her nephew "is a national hero."
No one else was reported missing from the flooding, police said.
Howard County County Executive Allan Kittleman called the Sunday afternoon flash flooding worse than the one that hit Ellicott City in 2016, killing two people and causing over $20 million in damages.
“My heart's broken when I walk through the town and see it,” Kittleman told "Good Morning America" Monday. "All I'm thinking about is the folks whose lives have been devastated for a second time in two years."
Local toy store owner Megan Clark was at her business when the water "burst" through, rising from her ankles to her waist in minutes, she told ABC News.
"We expect water [but not] this fast. It came faster than last time," she said.
Crews, residents and business owners are now beginning to clean up the streets. More than 8 inches of rain was dumped in Ellicott City in just a few hours, washing away cars and damaging buildings.
“We are heartbroken to see the devastation," Hogan said in a statement Monday. “State agencies have been working around the clock to coordinate resources, begin assessing damages, and clean up debris, mud, and damaged infrastructure.”
ABC News' Elizabeth McLaughlin and Sarah Shales contributed to this report.