DeGeneres, who lives in the same community and had dinner with Lowe a few days earlier, could relate.
"I think people who live there, we kind of are holding onto each other," she said, "because we really know what it's like."
Lowe gave the audience an update on the situation there.
"It's still unfortunately 20 dead," Lowe said. "They did find one of the missing alive two days ago, but there's three missing as of today."
In addition, the actor said 179 homes have been destroyed and more than 200 homes are damaged.
"They'll have to be scraped," he said. "When they talk about the destroyed [homes], they're really destroyed. The homes that are still standing will eventually have to be wiped out, they don't even really talk about, because it's so extensive."
Lowe was out of town during the mudslides, which happened after a torrential rainfall fell in the same area the state's largest-ever wildfire had burned weeks before.
Lowe said he received a video call at 4 a.m. from his son Matthew, who was home at the time.
"Fires [were] everywhere, because gas lines were rupturing," Lowe said, describing the picture his son showed him. "It was like Armageddon."
"People who saw the fires, they woke up, went out to see what was going on, and then were washed away," he continued. "It was, truly, a perfect storm of bad events."
Lowe then shared footage of the destruction -- including flattened homes and parts of the freeway covered in mud -- and the cleanup effort that is already underway.
"There are stories of hope that we have to focus on," DeGeneres said, mentioning a couple who found their cat still alive after tracking its footprints in the mud.
"There are so many pets that nobody talks about," Lowe said. "One of the big, huge, tough firemen had tears in his eyes talking about rescuing an iguana. I was like, 'Yeah! Iguanas are people, too!'"