For the approach (to Borealis Pass), see the Main Page.
From Borealis Pass (7,680+ ft), turn left (north) and scramble the west side of the ridge for about a half-mile to the small basin below Pinnacle's south side. Hike sandy and rocky terrain to the saddle immediately below the steepening south slope. From here one gets an impressive view of the east and SE-facing cliffs. A fairly straightforward scramble up the steep slope gains the upper crest of the summit (minor scrambling to gain the crest). Turning right, scramble the west side of the fin-like crest to the highest point. Class 3 max.
Time = 1-2 hours from Borealis Pass, 3-4 hours from the Entiat River Trail, 6-8 hours from the car.
Reverse the route back to the pass and subsequently to camp/home.
Alternate shortcut from Sheep Driveway Trail:
About 0.2 miles before Borealis Pass where the trail makes a bend to the right at 7,400 ft, continue straight (NE) into the small basin below Pinnacle. This saves a little time and the necessity to scramble the ridge crest immediately north of the pass.
The North Side Scramble of Peduncle Pinnacle
Note: "Peduncle Pinnacle" is my name for Pt. 7495. I could claim a first ascent of it since I found no evidence of prior visitation at its summit. It's a strawman claim for sure.
About 0.4 miles due west of Borealis Pass is Peduncle Pinnacle (Pt. 7495). If you've some time to kill, this little rock promontory offers a fun little 300-ft class 3+ scramble on its north side. From the saddle on its east end where the trail comes up, contour around to the back (north) side. Make an angling descent of a few feet on dirt below the granitic rocks to a low point. Pick a route up large boulders and ledges to gain the crest immediately east of the high point. Make an exposed class 3 move or two on the crest then drop left through small trees onto the south side. Scramble to the top on the right. To the west about 40 feet away is another rocky top that is about the same height. Both are doable from the south side. Return the same way.
It may be possible to scramble the spine all the way from the saddle on its east to the summit. This will surely entail harder climbing than the previous paragraph's route. The first and probably only real difficulty would be the first step (twenty feet of class 4).
Both routes will take less than an hour to complete. Half-an-hour seems likely.
The south side of Peduncle Pinnacle is an uninviting corrugation of gullies and treed ribs--not at all aesthetic to a leisurely scramble.
No technical gear needed for the Pinnacle Mountain south route or the Peduncle Pinnacle scramble.
Ice axe would be handy in early season since there is steep terrain to negotiate.