Residents in the town of Maalaea and parts of Kihei were sent an evacuation notice on their phones, and flights to the island were diverted.
"@Oprah Maui is on fire consider opening the ranch road so we can get upcountry," one wrote.
"@Oprah there's a huge brush fire on Maui right now! People are trying to evacuate Kihei-my husband and son included!" one resident tweeted. "If you would kindly share the code to your gate/road, folks can evacuate through Kula."
Winfrey responded that she had given immediate access to her private road.
"Hi there Jack, Access to the road was given to county officials immediately. This was many hours ago. Hoping for the safety of all," she wrote.
Hawaii's Governor David Ige tweeted his appreciation.
"A big mahalo to @Oprah for giving @mauicounty access to your private road for use to assist in the #Mauifire," he tweeted.