This is an alternative to the Irving Creek approach to Irving Lake, and *might* offer a reasonable alternative to the Rock Lake/Moon Lake approach to the likes of Irving Peak and Mount Oso. It is steep and requires gaining an extra 400 feet (over going up Irving Creek), but it minimizes deadfall and bushwhacking.
The trailhead is located at the Vallecito campground at the end of CR 500, north of Vallecito Reservoir. There is free parking immediately after the pavement ends. Hike up the Vallecito Creek Trail (#529) for 6.8 miles to where the 3rd bridge over the creek was destroyed by an avalanche years ago. Here you have a good overview of the route up the avalanche path on Pt. 12,505
1.
When Vallecito Creek is low, it should be possible to hop across on rocks just downstream from where the trail intersects the creek. In normal conditions, plan to wade across. The current can be very strong, and crossing may be dangerous or impossible during spring runoff.
Cross the creek and continue up the trail. After 0.8 miles (around 7.6 miles from the trailhead), locate the obvious weakness in the cliff band at the base of the slope to the right (east). Leave the trail here, cross a meadow, and climb through the break in the cliffs
2. The easiest passage may be to the right initially, but once above the cliff make your way to climber's left side of the avalanche path.
Hike straight up, staying on the border between the forest to the left and young aspens to the right
3. In general, heavy deadfall can be bypassed to the right, and thick aspens can be bypassed to the left. Wherever rocky walls press in from the left, traverse left to hike up and over them, staying out of the aspens below
4.
Around 10,200', hike up a patch of talus at the edge of the forest. Above this, bear right (east) onto the open slope, aiming for a gully below obvious slabs at 10,500'
5. Continue up this gully on game trails and talus for around 400 feet
6. When the left side of the gully opens up to a steep grassy slope, exit the gully to the left and climb up the slope to where the upper edge of the forest meets a talus field at 11,000'.
Hike north along the border of the forest and talus briefly, then traverse across the talus up to the top of a small aspen stand with an excellent view of the south face of Mt. Irving
7. Again hike north along the border of the forest and talus to reach a grassy strip descending from the right
8. Look for a flat area above and left of the grass strip, visible through a break in the trees. Climb up the grassy slope, traversing slightly left to reach the flat area at 11,400'
9.
Follow this elevation contour around the corner and proceed across the west-facing drainage, staying at or above 11,400' to avoid the steep, rocky gullies in the drainage
10 12. Continue into the trees to the north of the drainage
13, where you should encounter a well-traveled game trail descending steeply to the west
14. Follow this down 150 - 200 feet to bypass a hidden cliff band
15, then angle north towards the base of a large talus field. Continue descending north across the west edge of this talus field and enter the forest around 11,100'
16. Maintain this contour through the forested area, negotiating a creek and some deadfall, to reach the talus slopes on the other side.
Hike along the grass beneath the talus slopes, towards the Irving Creek cascades
17 18. Staying right (east) of Irving Creek, follow game trails past the steep lower cascade (a worthwhile rest stop with a nice pool at the base
20). Cross the creek easily at a flat area with a pool below the upper cascade and follow game trails up to the slabs left (west) of the creek
19. Hike up the slabs and either traverse above or pass through a willow thicket to reach the outlet of Irving Lake
21.