Dewey Peak is a secluded peak over looking Dewey Lake. While the peak is the road less traveled, Dewey Lake is a very popular destination for hikers and campers using the Pacific Crest Trail (PCT). When you reach the Dewey Lake fork on the PCT, look down on the lake, Dewey Peak is the peak on the left. (It is not identified on the map) Seymour Peak is on the right. Standing here you can start planing your route to the saddle between the two peaks.
There is no clear trail after getting to Dewey Lake so you will have to bushwack a bit and havesome route finding skills. Starting at Dewey lake the first way point is the South end of the small lake lying to west of Dewey Lake. Once at the south end of the small lake go S/SE (error to the east) a bit looking for climbers’ trails/game trails heading uphill (due South) toward Dewey Peak – You cannot head uphill directly from the south end of lake as it is buttressed with small cornices and cliffs. Just East of the buttressed zone is a small drainage valley which you should also avoid as it turns into a ravine as you ascend. You need to head east enough to be on the east side of this gully/drainage. It is bushwhacking for the first 700 feet of ascent finding the path of least resistance but generally staying on a 180 T bearing heading uphill.
At about 5800 ft you will break from the tree line, you may beable to look left at this time and get a good view of Dewey Peak. You should have a clear view of the saddle from here. If you bear to far left (SE) you will end up at a cliff underneath summit block. So if you error, error to your right a bit. Ascend to this ridgeline leading to Dewey where you will find a climbers trail following ridge to the summit block. Another detail to mention would be when gaining Dewey Peak towards the summit block, do not traverese too far east or left as you leave the Dewey/Seymour saddle because you will be caught up in a rock buttress requiring you to down climb to go around.
As you near the summit block, you must cross a steep rocky gully/cirque near the summit. After crossing this gulley face a bit further you will be just below the summit block. Scramble up a few feet of loose rock debris to the base of the summit block. You should be at the W/SW side of summit block which looks pretty imposing. Facing the summit block rotate left a bit (toward NW), around base of summit block to the top of a rock filled gully (previously crossed below). This face is generally used for the scramble type climbs to the summit. It is about 80 feet to summit from this point so if you plan to rappel off, It would be good to have a 60 meter rope. The easiest route starts at the top of the gully (which is also a small saddle) and traverses right upward across the face, then a couple vertical moves (which are the crux) before gentling out a bit on broken rock & dirt traversing back left to the summit. Problem is the further right you traverse the more exposure encountered! Slightly more challenging rock climbing is encountered by not traversing so far to the right and lessening the exposure. There is very little in the way of a reliable rappel anchor on the summit itself (which is plenty large for a party of 5-8 people). There is a boulder at the top that is slung x3 with a repel ring. Check the slings for wear and replace as needed. You may want to find additional anchors points for additional safety. As indicated the rappel was about 80 feet from this point.
Drive to Chinook Pass on Hwy 410 – Approx 1 hr 50 min from Tacoma (allow 2 hrs). At Chinook Pass parking area take the PCT to Dewey Lake trail branch.
You can also enter from the entrance Tipsoo lake . If starting at Tipsoo, intersect with PCT S/SE of Naches and follow PCT to Dewey Lake trail branch.
Round trip from parking lot about 7 ½ miles. Total elevation gain about 3100 feet (2200 feet to summit and 900 feet returning).
There is a permit station shortly when leaving MRNP.
Route finding skills are necessary. Don't go without a map and compass and GPS is real handy too.
Because of all the loose rock check all hand and foot placements, also a helmet is highly recommended for the last sections of the climb. Because of the poor rock, there are not a great number of places to place protection if you choose to use it.
When To Climb
I would suggest only doing this route only after the snow levels have receeded. If doing in snow, I would be seriously concerned about crossing the gulley face just below summit block.
There is plenty of camping available along the PTC and at Dewey Lake. Please follow the posted rules on fires and where to camp.
There are some very nice views of Mount Adams and Mount Rainer from the top.