Police initially reported that officers rescued two people and a dog from inside a Bellevue, Washington, home on Monday morning, but authorities later confirmed the residents escaped on their own. Police say it’s possible flooding was the cause of the home’s collapse, and within two hours of the home sliding off its foundation, 42 people and several pets were evacuated from 17 homes.

Bellevue Police posted on Twitter that the number of evacuees is likely to increase and fire crews were checking other homes for damage. Crews were working diligently to find the source of the water, utilizing an unmanned aerial system.

Newsweek reached out to the Bellevue Fire Department for comment but did not receive a response in time for publication.

“We heard his huge sound, it was like an earthquake,” a neighbor told KOMO. “I looked out the window, and I saw one house slide completely down the hill.”

The house was sitting at a 45-degree angle. Footage from the scene showed the house sitting on the side of a hill with debris scattered nearby. Police warned the area is unstable.

After the house collapsed, police made reverse 911 calls to people in the area informing them of the need to evacuate, according to KING 5. Evacuees are being offered shelter at the South Bellevue Community Center. It’s unclear when evacuated residents will be able to return to their homes. So far, there have been no injuries reported.

Washington is one of the most landslide-prone states in the country, according to the Washington Department of Natural Resources (DNR). Experts from the DNR were called to the scene to help investigate the cause of the collapse, although it’s unclear if the water main break was the source.

KING 5 reported that it’s not surprising a landslide occurred in the neighborhood, which is in a hilly area of the state. However, it’s unclear if the water main break happened first or if the collapse happened first.

A man who lives across the street from the collapsed home told KING 5 he heard what sounded like thunder and heavy water, which he assumed was heavy rain. When he went outside, he saw the home had collapsed. He said the water was flowing so strongly that he couldn’t cross the driveway to get into the house.

“I was just worrying that he and his wife were trapped inside,” the man said of the homeowners.