The crash was reported at about 1:55 p.m. on the highway at Los Alamos Road, according to CHP Officer Peter Van Eckhardt.
Two people were reportedly trapped inside a blue sedan after it crashed into a tree and caught fire. One person died and the other was taken to a nearby hospital, Santa Rosa police Sgt. Lisa Banayat said.
Van Eckhardt said around 3:15 p.m. that both eastbound and westbound traffic was being diverted onto Melita Road.
Motorists are advised to avoid the area if possible.