Herlihy Peak
Peak · 11,758 ft · Mammoth Lakes corridor
Herlihy Peak rises at 11,758 feet in the Mammoth Lakes corridor of California's Sierra Nevada. A high-elevation rock and talus summit, it sits exposed to westerly wind funnels and afternoon downdrafts off the Sierra crest.
Wind dominates; expect sustained 12 mph average with afternoon gusts to 31 mph common. Morning calm windows narrow to dawn hours. Temperature averages 31 degrees Fahrenheit across rolling 30 days. Avalanche terrain demands snowpack awareness in spring; slopes below the summit drain fast and can slide without warning.
Over the last 30 days, Herlihy Peak has averaged a NoGo Score of 36.0, with wind holding steady at 12 mph and temperature locked near 31 degrees Fahrenheit. The week ahead will track similar patterns; morning ascents before 10 am offer the best stability. Wind peaks mid-afternoon and remains the prime constraint for approach windows.
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About Herlihy Peak
Herlihy Peak stands at the north end of the Mammoth Lakes corridor, accessible from the town of Mammoth Lakes via Highway 395. The peak sits in the high country between Mono Basin drainage and the Owens Valley. Access typically begins from trailheads near the Sierra crest approach roads; approach timing matters as much as route choice here, since afternoon wind makes exposed ridges and open talus fields difficult to navigate. The peak itself is non-technical rock scrambling once you gain the ridge; the real constraint is the weather window to get there.
Spring and early summer bring the widest conditions swings. Snowpack remains into late spring, adding avalanche hazard to the steeper aspects below the summit. The rolling 30-day average wind of 12 mph masks afternoon peaks to 31 mph, which arrive predictably by midday on most days. Temperature averages 31 degrees Fahrenheit through the rolling window, but annual extremes range from 17 degrees Fahrenheit in winter to 47 degrees Fahrenheit in late summer. Crowding is minimal year-round, with an average of 2.0 on the popularity scale.
Herlihy Peak suits experienced ridge travelers and scramble-comfortable alpinists who plan around wind and snow. Expect to start before dawn if afternoon wind is a concern. Water is scarce above the Sierra crest; melt occurs late into summer even after lower elevations green up. Afternoon thermal wind is reliable enough that you can plan rest days around it. The 30-day maximum NoGo Score of 65.0 happens during windy, cold snaps; minimum scores of 5.0 occur on calm mornings with stable snow. Parking at trailheads fills only during holiday weekends and remains uncrowded the rest of the year.
Nearby peaks like Mammoth Mountain and the Ritter Range crest lie within a day's approach loop. The Mammoth corridor sits higher and more exposed than Yosemite Valley at the same latitude, creating stronger afternoon wind patterns. Access roads via Highway 395 are open year-round but snow chains are required winter through early spring. Avalanche hazard assessment should follow Eastern Sierra Avalanche Center bulletins, especially for north-facing gullies and wind-loaded ridges.