Not recommended -- it's okay most of the way, but gets ugly traversing the crest above the Nohokomeen Glacier. Descended the standard south face for a 12-hour car-to-car day. Trip report.
It's been many years since I climbed this. I attempted 3 times, my friend 5, before we finally made it. You must persevere until you conquer! We tried it with 5 or 6 people once, usually turned back by weather or route finding. Finally made it just the 2 of us, in 22 hours from the car and back! One of my favorite climbs of all time!
Many words could be used to describe this trip. Definitely one of the more exciting climbs I've ever done. Partly due to weather it took us 4 days to climb this peak and we had an unexpected "bivy" which was quite cold that night. Going up Jack Mountain I felt fantastic thinking to myself "This is Mountaineering as it should be!". But on the way down reality sank in with what we were dealing with, especially the repel section. Jack Mountain without a doubt had the worst repel I have ever had. I was quite frightened by it. Perhaps if I planned it out a bit better I could have made it safer, but even with careful planning it would be lousy at best. I was very happy to have brought an ice tool on this trip. Personally I think we hit this mountain at pretty much the best time when the upper slopes are still covered in snow making it "reduced loose rock". But even then there is still loose rock. I had a blast kicking in steps which I very much enjoyed that aspect of the climb even at it's most steepest portion of the climb. I admit I don't think it would be wise for me to return to this peak. I did however have a fun time, despite it's epicness. But this is no peak for an inexperienced person!
After three attempts, one from the north and two from the south, I am finished with Jack Mountain. Not for the faint of heart is a good description. The physical demands and loose exposed scrambling were no joke. The best part of the climb was the steep upper snowfield. Thankfully, I had Josh Lewis kicking in steps and an extra ice tool. We would recommend at least a 40m rope for the rappel. Having only a 30m rope made things quite interesting!
Was so close to the summit but the snow conditions deteriorated pretty fast after the sun came up. We almost made the summit, but at least I had a very good time on the mountain. This was certainly no easy 9,000 footer, and I see why it is rarely climbed. So the Jerry Lakes route as others say has a lot of up and down involved. I also kinda wish I had a ice tool for my non ice axe hand. But it was certainly worth my while!
I must echo what setrent said. The route finding for the Jerry Lakes approach was reasonable. The lakes make a nice camp spot.
Crampons and axe are definitely useful on the snowfield leading up to the face. The face is largely loose 3rd, with a short section of 4th (or easy 5th) at the bottom. A rope, while not necessary, was comforting, particularly on the descent of the crux.
Not a technically demanding mountain, but it is strenuous. It took our party about 6.5 hours from the TH to camp, and another 5.5 hours or so from camp to summit.
RT was 22 miles, with about 11,000 feet of gain.
Having approached the South Face by Little Jack and Jerry Lakes, I would recommend the Jerry Lakes approach. The route finding is simple, and the lakes provide excellent camping. The approach to the face from the lakes is straightforward also. Allow five hours minimum from the car to the lakes, and four hours from there to the summit. Ice axe and crampons required for the glacier, especially in late season, but no rope needed for the climb. The face is mostly loose unprotectable third with a short pitch of fourth class climbing. Bring helmet.
This climb had the longest approach I have been on thus far, especially when loaded down with 85+ pounds. Like most areas in the fall / winter 2002, Jack was was unseasonably dry. As a result, I carried up 7 quarts of water. It was a good thing, because I found areas with only trace amounts of water.
Other than lack of water on the mountain, the conditions were great. The weather was very clear, and lows were down to a crip +20 degrees with 0 wind in the evening. I awoke from camp at 3:30 AM on top of Little Jack to see fresh cougar tracks right next to camp, but that was the extent of any "wildlife" that I had seen the entire trip. There was encounter with a large fire at about 5500 feet very near the trail, which was quite demoralizing. The rangers had informed that the fire was "under control" two days prior to me setting out for Jack, but this fire was not finished burning. This became an increased incentive to kick things in high gear, and get way up above it. Fortunately, the fire had stalled, and was smoldering out the following day on my descent.
Once on massif of Jack, there was lots of scree and, and occasionally some large rock movement. Trying to find a route with more stable rock was almost futile. A very long approach, but a well-rewarded weekend.