The Jenny Lake Ranger Station (see map) is the center for climbing information and registration in the park from early June to mid-September. Climbing conditions are the best from mid-July through late September, although afternoon thundershowers are common in these months and an extended period of poor weather with snowfall usually occurs in late August. May and June feature long periods of poor weather with heavy precipitation, some snow, and subfreezing temperatures. Heavy rockfall and some avalanche activity are common. Major storms occur in late September and early October with snowfall and icing conditions on most routes. Winter weather in the Teton Range is severe: heavy snowfall, high winds, and extreme temperatures. Avalanche danger, usually present, is frequently high December to June. [Illustration: Climbing equipment.] [Illustration: _Hard, crystalline rock and an alpine panorama make the Teton Range a mountaineering mecca._] Registration and Information. Because of the hazards and possibility of accidents in mountaineering, the National Park Service requires all climbers to register in person before climbing and to sign out in person after climbing. From early June to mid-September this is done at the Jenny Lake Ranger Station. It must be done at Moose Visitor Center the rest of the year. Notes left at the ranger station are not acceptable registration or sign-outs. (Climbers returning after the ranger station is closed may sign out at the Late-Returning Climbers Registration Box on the ranger station porch.) Registration is regulated under the Federal Code of Regulations. The mountaineering rangers on duty provide current information on the nature and condition of climbing routes, equipment and experience requirements, and time factors. Request general mountaineering information from the chief ranger at the park address. Guidebooks, maps, and photographs of various peaks and routes are available at the Jenny Lake Ranger Station to help you plan climbs. In winter—mid-September through May—information and registration are available at the Moose Visitor Center. Conventional mountaineering equipment is satisfactory for summer climbs. Ice axes are essential and crampons may be desirable for early season climbs and for some routes throughout the season. Climbing helmets are strongly recommended for technical climbs and for climbs exposed to regular rockfall dangers. Climbing equipment and food suitable for backpacking may be purchased in the area. Limited selections of rental equipment may be available. Low cost lodging for registered climbers is available at Grand Teton Climber’s Ranch, an American Alpine Club-operated concession. Write the manager at Moose, WY 83012. Boating and Floating