Mount Aggie
Peak · 11,548 ft · Mammoth Lakes corridor
Mount Aggie is an 11,548-foot peak in the Mammoth Lakes corridor of the Sierra Nevada. High elevation and exposure to westerly flow make it a serious objective during spring and early summer.
Wind dominates the exposed ridge; the 30-day average is 14 mph with gusts to 39 mph in afternoon. Early morning offers the calmest window. Temperature swings 9 to 36 degrees Fahrenheit across the year. Expect low crowds (average 2.0) but avalanche terrain requires winter awareness.
The 30-day average wind of 14 mph and score of 36.0 reflect typical spring conditions; afternoon gusts spike reliably. The week ahead will show whether the pattern holds or transitions. Crowding stays minimal at this elevation, but snowpack stability and wind loading are the real filters. Check ESAC forecasts before any winter approach.
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About Mount Aggie
Mount Aggie sits at 11,548 feet in the high Sierra above the Mammoth Lakes corridor, roughly 15 miles north-northwest of the town of Mammoth Lakes via Highway 395. Access is principally from the June Lake area or via trailheads off Highway 395 and secondary roads. The peak straddles exposed terrain with no substantial shelter; it is a high-altitude objective suited to experienced mountaineers and scramblers. Base popularity is low (0.2), reflecting its remote position and technical character. Most approaches involve approach from the west side via drainage systems and ridgelines; snow travel is common spring through early summer.
Spring and early summer dominate the climbing season. The 30-day average temperature of 23 degrees Fahrenheit and average wind of 14 mph define the typical pattern, with max gusts reaching 39 mph in afternoon. The peak sits high enough that snowpack persists into June; avalanche terrain is present, particularly on steeper north and east-facing slopes. The 30-day minimum score of 5.0 indicates windows of excellent conditions exist alongside stretches of marginal stability. Late September and early October offer warmer temps (up to 36 degrees at elevation) and more stable snow; winter brings sustained cold (minimum 9 degrees) and deep snow that demands avalanche knowledge. Crowding averages just 2.0 across rolling windows, so solitude is nearly guaranteed.
Mount Aggie suits experienced alpinists and off-trail scramblers comfortable with exposure and self-rescue. The typical user is a Sierra veteran with avalanche training and winter/spring scrambling skills. Plan around afternoon wind; head out at first light to summit before thermal flow strengthens. Winter and spring approach require current ESAC avalanche forecasts and knowledge of snow slab terrain on the north and east faces. Expect minimal services or rescues at this elevation and distance; self-sufficiency is mandatory. Parking and trailhead capacity are rarely bottlenecks given low base popularity.
Nearby peaks in the Mammoth corridor include Mammoth Mountain proper and the Ritter Range to the north. Mount Aggie is less trafficked and less forgiving than Mammoth Mountain's skiable terrain but offers similar high-Sierra character without resort infrastructure. Climbers comfortable on Mount Tom or Mount Morrison will recognize the style. The peak's isolation and avalanche terrain place it squarely in the domain of winter mountaineers and spring scramblers; it is not a summer casual destination.