Rock Slide Blocks Trail Creek Summit Road Near Sun Valley SUN VALLEY, Idaho (KLIX)-A rock slide and muddy conditions have blocked off a Blaine County road east of Sun Valley. According to the Blaine County Sheriff's Office, rock, debris and mud has made the Trail Creek Summit inaccessible to all travel on both sides. The Blaine County Road and Bridge is working on the roadway. A Flood Advisory was issued by the U.S. National Weather Service-Pocatello for central Blaine County earlier in the day. Heavy rains were expected in the area until at least 6 p.m. Some areas to the south could experience flooding.