The reason for the closure is because the fire has jumped the 120. The original fire started on August 17, as of earlier today, the fire has burned about 800 acres, but a more accurate number is expected around 7 p.m.
Evacuations have also been ordered in the Buck Meadows area along Highway 120, near Groveland. The evacuations have taken place in the last hour and the fire department doesn't know exactly how many homes were affected.
The fire started in a drainage area on Saturday, and has spread in a sort of a zig-zag fashion. Resources are there from many agencies, including Sierra National Forest, Yosemite National Forest, Kern Co Fire, Stanislaus Co and the Bureau of Land Management among others.
MORE INFO ON THE RIM FIRE HERE:
http://www.inciweb.org/incident/3660/