A wind-blown wildfire that has forced the evacuation of hundreds of homes south of the resort town of Jackson, Wyoming, prompted officials on Sunday to close 50 miles of a key highway traveled by tourists to reach Grand Teton and Yellowstone national parks. The Roosevelt fire has scorched nearly 40,000 acres of drought-parched landscape and destroyed at least four structures, including two dwellings, since erupting Sept. 15 in the Bridger-Teton National Forest about 30 miles south of Jackson. Hundreds of firefighters battled across steep, forested terrain and bone-dry sagebrush flats to push back flames driven by winds gusting to 50 miles per hour.