At about 17:00 MST, a Piper PA-24-250 was damaged during an off-airport landing 10 miles south of Jordan Valley. The pilot was not injured. The pilot left Pocatello Regional Airport VFR, with an intended destination of Boise, Idaho. He stated he was planning on flying an instrument approach into Boise due to low ceilings and fog, but had forgotten his instrument approach charts. The pilot attempted unsuccessfully to find a nearby airport where he could land under VFR conditions. Approximately one hour later, the pilot determined that fuel was running low and elected to make a precautionary landing on a road. During the landing roll-out, the aircraft collided with a road marker, damaging a wing and wing spar.