Island County Sheriff Mark Brown said no one was hurt, but one home was destroyed by mud and debris when the slide happened in an area near Alderwood Street and South Fircrest Avenue just after 4 a.m.
"It's a pretty massive slide," he said.
Officials said three people had to be evacuated via ATV and one person had to be taken out by boat. Brown said a relief center for at least a dozen other displaced residents has been established at a nearby community center.
It was not clear exactly what caused the slide, as there was no rain overnight in the area.
More details to follow.