SEATTLE -- Three people were killed Saturday and at least eight injured after a huge mudslide came down on homes in Snohomish County in northwest Washington.
County spokeswoman Shari Ireton said a 6-month-old infant was among those injured.
The injured were taken to a nearby hospital for treatment, said spokeswoman Jennifer Egger of Cascade Valley Hospital in Arlington. There was no word on their conditions.
At least six houses were destroyed, authorities said.
One witness said the slide came down right in front of him and "it was like darkness" covering the road.
Another man reported hearing the screams of a baby.
The estimated milelong slide of dirt, trees, rocks and other debris cut off the city of Darrington north of Seattle and is blocking the North Fork of the Stillaguamish River. State Route 530 was completely closed near the town of Oso.
The National Weather Service said the river level dropped from 3.1 feet to 0.9 feet in the hour after the slide occurred, confirming the river was blocked by slide. Geologists have been called out to determine how stable the area is.
Snohomish County officials advised residents upstream and downstream of the slide to prepare to leave their homes.
"We are asking residents to prepare their homes, pets, livestock, etc. for immediate evacuation if and when it becomes necessary," said Bronlea Mishler, Deputy Director of Communications.
Officials warned people to stay clear of all trestles and bridges on the north fork of the rive
The Red Cross has set up a shelter at a middle school in Arlington.
Authorities said they believe the slide was caused by ground water saturation from recent heavy rainfall.
The slide occurred just before 11 a.m. PDT Saturday and carried a house with people inside across a rural road, sheriff's spokeswoman Bronlea Mishler said.
Contributing: The Associated Press