Two people involved in the initial collision died at the scene, according to the Seattle Fire Department.
Another person involved in that initial crash was transported to Harborview Medical Center in critical condition.
At this time, it is unknown what caused the initial collision.
Three lanes of southbound I-5 were closed until about 8 a.m. while authorities responded to the scene, according to the Washington Department of Transportation.
WSP responded to the scene and will continue to investigate this incident.
