About This Route
Ellery Lake, at 9,489 feet along Tioga Road near Tioga Pass entrance, offers a remote high-alpine dive spot in Yosemite's eastern high country. Just west of the park boundary but fully within Yosemite, it's accessible via a short trail from the parking area. The lake features steep drop-offs, boulder fields, and possible trout schools, though viz is low (5-15 feet) with thermoclines at 20 feet. Summer surface temps reach 55°F, chilling deeper. NPS warns of no facilities or supervision; buddy system mandatory per national park water safety protocols. Nearby Olmsted Point provides scenic views en route. Ideal for experienced divers logging altitude dives, but prioritize conservation: no anchoring on fragile meadows.
Safety Considerations
Extreme altitude demands PADI Altitude Diver certification; compute NDLs conservatively with tools like MultiDeco app adjusted for 9,500 feet. Monitor for high-altitude pulmonary edema (HAPE); descend if short of breath. Entries via steep talus slopes risk slips; use spotters. Inflows from Ellery Creek create unpredictable currents; abort if windy. Consult Big Oak Flat or Tuolumne rangers for road conditions (Tioga closes November-May). DAN recommends flying restrictions 24+ hours post-dive. Visibility drops post-rain; carry reels for navigation. Follow NPS: never dive alone, check forecasts hourly.
Essential Gear
Heavy insulation like Pinnacle Cruiser drysuit, 80cf double tanks for margin, primary/backup lights (Halcyon), wrist-mounted compass, and dive alert marker. Thermal base layers prevent shock.