OverviewThe generically named Volcanic Ridge (11,500 feet) is a short side branch off of the southern end of the Ritter Range in the Ansel Adams Wilderness, approximately 6 miles southeast of Yosemite National Park. The ridge is aligned in a northeast-southwest direction and sits just east of the Minarets. Although visible from the Mammoth area, it is easily overlooked (literally and figuratively)in favor of the larger, more dramatic peaks just behind it, including Mt Ritter, Banner Peak, and the Minarets. The summit has an outstanding view of the spectacularly serrated Minarets and surrounding lakes.
Volcanic Ridge is class 2 from the north (from Ediza Lake) and southeast (from Minarets Lake). The steeper southwest side is probably class 4.
Although Volcanic Ridge is away from the crowds, this portion of the Ansel Adams Wilderness is one of the most heavily used areas because of its proximity to Mammoth Ski Area. Many Southern Californians see this area while skiing at Mammoth and say, “Dude, that would be a totally righteous local for summer backpacking.” This is why beautiful Thousand Island Lake is also known as Thousand Person Lake.
GeologyAlong with the rest of the Ritter Range, Volcanic Ridge is the remains of a long extinct volcano that was active well before the Sierra Nevada range appeared. Except for the Convict Canyon area, the surface rocks are older than all other parts of the Sierra. Erosion removed many feet of surface material so that what is now on the surface is colorful metamorphosed igneous rock that was once beneath the volcano. Like the Minarets, there is lots of loose, crumbly rock that is not that pleasant to hike and climb on.
Agnew Meadows is 2.6 miles beyond the ski/bike resort. From one of two parking areas for backcountry visitors, take the trail down to the San Joaquin River and take the trail past scenic Olaine Lake, past even more scenic Shadow Lake, and up to extremely scenic Ediza Lake. At Ediza Lake leave the trail and head south-southeast up the slopes class 2 slopes of Volcanic Ridge.
Devils Postpile is the other TH access to the Minaret area. From the ranger station, follow the trail across the San Joaquin River, turn north for a few miles, and follow the Minaret Lake Trail west to also scenic Minaret Lake. Leave the trail at Minaret Lake and head north up the class 2 slopes of Volcanic Ridge. This trail is sandy in the lower stretches and often hot on warm days. This trail is better as a descent route, and combined with an approach starting from Agnew Meadows, makes a fine loop route (you can take the shuttle bus for free from Devils Postpile back to Agnew Meadow).
In the event that Route 203 is closed, you can still reach these trailheads, but you'll have more walking to do. If the road is closed at Minaret Summit (usually in spring), you have 2.6mi (downhill) to Agnew Meadows and another 4mi past that to Devils Postpile. If the road is closed at Mammoth Mtn (usually in winter) you have an additional 2mi (uphill) to Minaret Summit. You are almost assured of having the entire Ansel Adams Wilderness to yourself if you choose to do these extra miles at these times. (Portions plagiarized from Bob Burd’s page on the Minarets. Thanks, Bob)