How to get there:
The mountain is located north of Missoula in Montana. Drive north on Hwy. 93 from Missoula to the small town of St. Ignatius. Continue 4 miles north of town, after approximately 3 miles you should see Ashley Lakes Road go right, continue one more mile along Hwy. 93 and locate Red Horn Lane, going right. Turn onto this road and follow it straight ahead as it starts climbing the lower slope. Higher up, there is a gate (open, drive through and close it behind you), then the road crosses a canal on a pretty new bridge (ignore any side roads). From here, this road is definitely a 4WD road. In fact, when I was there, this road was pretty rough and we needed a sturdy, high clearance 4WD truck to drive it.
Continue driving until the road ends, now at a pretty distinct ridge. There is ample parking for at least 5-6 cars at this spot. This trailhead is located at N47:22.423, W113:59.570, elevation approximately 1520 meter.
Previous parties have gradually improved the description of this route, I received valuable information from Bob Bolton. The following description outlines what is most likely the optimal route from this trailhead.
First, follow the trail that heads uphill from the parking area. Another trail forks right, it runs to Ashley lake and should not be taken due to very difficult terrain and vegetation. The trail that runs up the ridge is difficult to follow as hundreds of fallen trees block passage. Head uphill, you will recover the trail off and on, but overall, this trail is not of much help. You will pass over some bumps on the ridge, one where there is noticeable loss of elevation (as well as more fallen trees). When you reach about 7000 feet, 2130 meter, you can start to traverse off the ridge while still gaining some elevation. There is no point in going higher on the ridge, since the first part of this traverse is across pretty open terrain with few obstacles.
The first cliffs can be passed on their lower side as you aim for the best passage of a pretty continuous cliff band ahead. This crossing is at location N47:23.025, W113:57.103, elevation about 2200 meter, see the map. Continue more or less horizontally, perhaps slightly gaining elevation, while using natural ledges and local tracks made by animals to facilitate progress. The Ashley lakes are deep below you. You will see that a section with larger spruce trees comes next. Snow lingers longer here, when we hiked here on July 12. there was still up to 3 feet (one meter) of snow among the trees. Pick your way through and gain some elevation here. You emerge from the trees (and from the snow) pretty quickly as the route turns a corner. Continue in easier terrain and complete the traverse at location N47:22.565, W113:56.451, elevation about 2275 meter. This is the ideal place to exit from the traverse, you have steeper terrain above and below you.
Next, follows a very nice, but equally important part of the route. Continue gently uphill in order to reach the south side of Duncan Lake. Proceed below cliffs on the south side, very likely on snow, perhaps 10 meter above the lake on the upper end of a (snow) slope that ends directly in the lake. Turn a corner below a steep cliff, this will put you directly into a wide gully that runs uphill from the lake (ie. south). Ascend this gully, then continue as it becomes level until you see a natural location from where you can aim directly for the saddle east of a closed 7800 foot contour, see the map.
From here, do not descend, but contour left to the nearby ridge, perhaps descending just a marginal amount. Quite conveniently, you will now observe that you may descend only a few meters of moderate snow, enter a natural ledge along the bowl and traverse easily to the final slope that will gain the key east-west saddle (Main saddle). Thus, this route connects Duncan Lake with the final ascent of McDonald without any significant loss of elevation. Furthermore, the entire route from trailhead to summit is (YDS) class 2, unlike the class 3 descriptions that have been assigned by other parties.
From the main saddle, N47:22.353, W113:55.162, elevation about 2500 meter, proceed more left across almost flat terrain to the final snow slope of McDonald. This slope is best climbed with crampons and an ice axe, it starts out quite gentle and steepens to somewhere around 35 degrees near the top. Aim for the right side of the short, almost horizontal top ridge. This ridge is corniced to the north so be careful and traverse left to the highest summit while staying on the left (south) side of the ridge crest. (The two previous photos were taken from the summit.) The summit itself is trianguar in shape, the highest point being a snow dome, while the two other corners (besides the ridge you arrived from) have some visible rocks.
The route to this mountain is perhaps a bit unusual in the sense that one cannot see the mountain before arrival in the key east-west saddle. By then, the remaining way (in time and distance) is rather short. This picture, taken from the summit, shows the east-west saddle, the route ascending to this col from the right, further down making a 90 degree bend (again right) behind the rock having three snow slopes. The traverse that avoids the loss of elevation leading back to the ridge described above, crosses the snow field in this picture (taken from the key east-west col area).
I did this climb together with Dennis Poulin from Oregon. I wanted to do this climb with a partner and posted a request while still in Norway. Fortunately, Dennis replied and I am very happy for his good company on this climb.
We met for dinner in Missoula the day before, also organizing permits and agreed to drive with Dennis' truck, a big Toyota much better suited for the bad 4WD road than my rental SUV. (We did not know that the road was quite this rough based on earlier descriptions, so this was a fortunate decision.)
We met at 0400 the next morning and by the time we were ready to hike, it was already 0545. It took us about 2 hours to hike up the ridge, then another 2 hours to complete the traverse. We did not hurry and made several short stops along the way. We were pleased with the nice route from below Duncan lake to the key east-west saddle, since the descriptions we had read all indicated that a significant loss of elevation was unavoidable. We had another rest up in the east-west saddle before putting on crampons and climbing a fine line to the very top of McDonald on snow. Arriving there at 1245, exactly 7 hours including numerous (short) breaks. The views where nice all around; Mountain landscape and true wilderness. McDonald Lake, a reservoir built in 1965, to hike here from there does not look any easier. More to the north, a true natural lake, the entire area looks pretty rugged.
After 40 minutes on the summit, we started our descent. We had another major rest below Duncan lake, traversed back in about 2 hours and arrived at the car by 1900, about 5.5 hours on the return, all in all a full day of hiking.
Dennis drove his truck expertly back down, we later had a nice dinner of celebration at the restaurant in the Doubletree hotel together with our wives, a long, but very complete day had come to an end.
Heidi and I would now drive into British Columbia and look for a couple of Canadian ultra prominent summits.