KPMG contacted Golf Channel during the telecast on Sunday, unbeknownst to Lewis.
Hurricane Harvey has killed around 50 people and unleashed massive flooding that damaged up to 50,000 homes in Houston.
Stacy Lewis scored one of the most popular victories of the year as she held off a strong challenge from In Gee Chun to clinch the Cambia Portland Classic title in Oregon. "I was able to go 4 under par after that point which was really important and help me get to 10 under".
The 32-year-old American looked well on course to be able to hand over the United States dollars 195,000 (£150,000) first prize when she started the day with a three-shot lead over the chasing pack and then birdied the opening two holes.
"I have been motivated", said Lewis who on Saturday shot a 65 to take a three-shot lead into yesterday's final round of the LPGA Tour's Portland Classic.
And of all weeks, Lewis ended it here. "Anybody who has seen me play knows that's not normally me, but I haven't anxious about anything", said Lewis, whose husband is a golf coach at the University of Houston.
She came out this week in Portland firing on nearly all cylinders and finished tied for fifth, her fourth top-5 result of the season.
There was the pressure that comes for a player of her stature having gone 83 events without a win.
She said she's looking forward to next week and trying to lock up a victory before the season is through, perhaps even, at the year's final major. She and Chadwell bought a house in northeast Houston about a year-and-a-half ago.
"It was pretty cool", Henderson said of her shot on the 11th. She announced the day before the tournament started that she would donate her winnings from the week to the relief effort. "I will just try and continue that trend over the next two days".
Lewis, 32, is a Toledo, Ohio, native who grew up in the Houston area and remains closely tied to the region.
Miyazato admitted she got emotional on the final hole of the tournament, and reflected on what she was going to miss the most about playing on the LPGA Tour.
Lewis was making her 83rd start since her last victory.
With 11 LPGA Tour wins already under her belt, Lewis commented: "It would honestly probably be one of the most special". If she finished second she would earn $120,000 (3.9 million baht).
"I'm excited to kind of get that monkey off my back and know I can do it, that I can hit the shots I need to and hit the putts when I need to", Lewis said.