Winfrey provided Instagram videos of her feet wading in deep mud in her backyard, and a rescue helicopter flying overhead.
"This is how deep the mud is," she said, sloshing through the muck up to her knees. "And the house in back is gone."
"What a day! Praying for our community again in Santa Barbara," she wrote.
Montecito is known as the home to a number of prominent entertainment industry figures. Many of them were sending messages of support to neighbors whose lives or homes were lost.
Rob Lowe wrote: "Mourning the dead in our little town tonight. Praying for the survivors and preparing for whatever may come. #Montecito."
He also noted that his neighbor Winfrey's home was being used as a staging ground for helicopter rescues.
Mourning the dead in our little town tonight. Praying for the survivors and preparing for whatever may come. #Montecito— Rob Lowe (@RobLowe) January 10, 2018
Ellen DeGeneres tweeted a picture of her neighborhood and wrote: "This is not a river. This is the 101 freeway in my neighborhood right now. Montecito needs your love and support."
This is not a river. This is the 101 freeway in my neighborhood right now. Montecito needs your love and support. pic.twitter.com/jRNCBrp4b5— Ellen DeGeneres (@TheEllenShow) January 9, 2018
Retired Cowboys quarterback and TV analyst Troy Aikman wrote: "Montecito has been a special place for me and my family for many years but it's a place that's been hit hard in recent weeks. My prayers are with all of those impacted by the latest mudslides."
Model Bella Hadid noted that she grew up in Montecito and was devastated to see her hometown under water.
"Completely under water," Hadid wrote. "I really can't believe it. I am praying and thinking so much for our friends in the hospital and their families that are still missing."