More than 50 people have been rescued already but many places are still inaccessible.
DeGeneres said on her talk show that the town is a "tight-knit" community.
He had earlier tweeted that Winfrey's home was a "staging ground for helicopter rescues".
Mud blocked Highway 101 along the Pacific Coast, and search and rescue teams are working their way to about 300 people trapped in their neighborhood in Montecito where the roads are inaccessible, according to Brown.
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Indeed, it was raining in Las Vegas on January 8 and 9, a rare occurrence for a desert city. Google employees used buckets to empty the water from the display.
The first confirmed death was that of Roy Rohter, the founder of St Augustine Academy in Ventura.
Thomas Tighe said he stepped outside his Montecito home in the middle of the night and heard "a deep rumbling, an ominous sound I knew was. boulders moving as the mud was rising".
But by then, tons of mud, trees, rocks and other debris were rolling down hills that had been burned in the largest fire on record in the state.
But the wooded hillsides that once gave their estates a sense of seclusion were largely denuded by last year's historic wildfires, setting the stage for the massive slides that slammed into homes, turned highways into raging rivers and shredded cars into almost unrecognizable tangles of metal after heavy Tuesday rains.