West of Mammoth Lakes, California sits the broad volcano called Mammoth Mountain. At 11,053 feet it is a playground for many outdoor pursuits in the Mammoth Area. Everyone from downhill mountain bikers to climbers will find recreation on the broad slopes of this peak. A direct climb can be the perfect day if you are pressed for time as you can park right at the base.
The summit is more traveled by gondola riders, skiers and mountain bikers. As with most ski villages at least 1 peak has to be sacrificed to the tourist god, Mammoth is the lamb of the area. This mountain is well worth climbing off trail with many steep yet enjoyable routes to the summit. The Ritter range and Minarets command views to the north. There are mutiple views to the south including Bloody Mountain and many lakes.
The mountain was formed from a long series of eruptions that started about 200,000 years ago and lasted to perhaps 50,000 years ago, although the volcano is still active with minor eruptions; the largest of which was a minor phreatic (steam) eruption 600 years ago. Mammoth Mountain is composed primarily of dacite and rhyolite; some of which have been altered by hydrothermal activity from fumaroles (steam vents). Mammoth lies on the South end of the Mono-Inyo chain of volcanic craters, some of which erupted as recently as 250 years ago.
Mammoth is outgassing large amounts of carbon dioxide out of its South flank, near Horseshoe Lake. The concentration of carbon dioxide in the ground reaches over 50%. Measurements of the total discharge of carbon dioxide gas at the Horseshoe Lake tree kill area range from 50-150 tons per day. This high concentration causes trees to die in six regions that total about 170 acres (0.688 km²) in size (see photo, below). Camping has been prohibited in the tree kill area since 1995, to prevent asphyxiation of campers due to accumulation of carbon dioxide in tents and restrooms.
Volcanic unrest since 1980 in the vicinity of Mammoth Lakes in the southern part of the Long Valley caldera has increased concern among scientists over the possibility of a volcanic eruption in the future.
Mammoth is situated between the Yosemite area to the north and Bishop area to the south. The village of Mammoth Lakes is the perfect staging point for many High Sierra adventures. The approach to the village is scenic driving from the north or south.
From Los Angeles, take I-5 north to State Route 14 north to US 395 north to State Route 203 (307 miles).
From Orange County and San Diego, take I-15 north to US 395 north to State Route 203 (375 miles).
From San Francisco & Sacramento, take Interstate 80 to Hwy 50 to the Kingsbury Grade cutoff to Hwy 395 south to Hwy 203; 320 miles.
From Las Vegas, take US 95 north to Hwy 266 west; turn slight left to State Route 168 to US 395 north to State Route 203 (310 miles).
From Reno/ Lake Tahoe, take US 395 south to State Route 203 (165 miles).
Mammoth Ranger Station, Mammoth Ranger District
Inyo National Forest
P.O. Box 148, Mammoth Lakes CA 93546 USA
Mammoth Mountain is open year round. In the winter it is open for Downhill & Cross Country ski. During summer months this is very popular for Mountain Biking. No entrance fee required.
When To Climb
The mountain can be climbed at any time of the year. Summer ascents could be dangerous due to most eastern approaches involving steep scree fields and loose unstable rocks on "solid" climbing spots and unsafe late season snow.
Due to the volcanic activity on this mountain it is not advised for camping. There are many gentle areas one could find for camping regardless. Overnight permits required.
Inyo National Forest
351 Pacu Ln
Bishop CA 93514 USA
Mammoth Mountain boasts one of the longest ski seasons in the country, extending from November until June. The yearly snowfall average is 400 inches and 300 days of sunshine per year.