The second story of a El Reno motel collapsed in the Saturday night storm, officials said.
Amanda Eller says the 17 days she was lost in the Maui forest were "the toughest" of her life.
The victim's family said he had gone for a swim. Officials described the waters as calm and clear.
35-year-old Amanda Eller went hiking alone in Maui, leaving her cell phone in her car, and was more than found two weeks later, barefoot and skinny, at the bottom of a ravine.
Millions across the United States are on alert for severe weather after a week of deadly storms. The swelling Arkansas River is threatening communities in Arkansas and Oklahoma, forcing thousands to evacuate.