Jack Mountain is located just east of the south end of Ross Lake in the North Cascades of Washington State. The mountain stands aloof, as there is no mountain that comes within 900 feet of it height for quite some distance in every direction. The closest high mountain is Crater Mountain (8,128 ft) three miles to the SSE. Prominent Jack Mountain can be seen from almost every other high mountain in the North Cascades. The Nohokomeen Glacier mantles the broad northern cirque. Jack has no easy summit route. The shortest approach is from Little Jack to the SW, but an approach from Jerry Lakes to the SE is also feasible. Some parties climb the mountain from the North via the North Ridge. The easiest route is up the South Face, but this face is comprised of very steep, loose gullies, cliffs, and snowfields. Definitely not for the faint of heart. Not many parties make the ascent in any given year.
At 9,066 ft, Jack Mountain ranks at 14th on the Washington Top 100 Bulger List and 17th on the Top 100 by 400P list. It also ranks 15th on the Washington Prominence List with 4186P. Yes, by all measuring accounts, Jack is a big mountain. You can see Jack off in the distance from m(an)y mountain porn viewpoints.
So how did this high, prominent summit come to exist? It stands so aloof. There must be a reason. Well, according to my out-of-print geology book called "Cascadia" by Bates McKee, Jack Mountain got that way because of the eponymously named Jack Mountain Thrust Fault, whose root was the Ross Lake Fault. To qoute from the book (page 97), "The Jack Mountain Thrust...postdates the marine sedimentation [of Cretaceous Rocks] in the Methow Valley. Paleozoic strata in the upper plate of the thrust moved eastward over the uptilted and eroded edge of Harts Pass [of the Methow Graben] and older formations."
For you Internet History buffs...
This was climbing bum Klenke's very first mountain page on Summitpost. He later adopted an assortment of other mountains put up prior to this page, but this was his first page for all intents and purposes.
Follow SR 20 (North Cascades Highway) to the East Bank Trail trailhead at Panther Creek. This is 18.5 miles east of Newhalem by road. Follow the East Bank Trail for 2.4 miles westward until you arrive at the multi-junction. The rightmost trail goes up to Little Jack (6.0 miles). From Little Jack, continue northward on the ridge to the notch and then traverse over to the base of Jack Mountain. Another approach is from the Crater Mountain Trail: from Canyon Creek trailhead 3.4 miles east of Panther Creek, take the McMillan Park-Jackita Ridge Trail to the Crater Mountain Trail junction (3.7 miles). Another 5 miles or so of mostly cross-country travel gets you to Jerry Lakes (consult a map). From Jerry Lakes, it is a simple matter to cross cross-country to the base of the South Face of Jack.
Permits are required for camping on the east side of the Little Jack ridge crest. This side is in the Pasayten Wilderness. The west side of the crest is in the Ross Lake Recreation Area. The distinction between what is east and what is west of the broad ridge crest is sometimes blurred. However, the chances of seeing a ranger on the ridge are minimal, so don't worry about it. In late summer/early fall, a goat hunter may be seen in the area. Apparently, between hunters, the Crater Creek basin is a prime area and hunters feel lucky to draw that basin in the lottery. The trailhead is only accessible in the summer as the North Cascades Highway is closed in winter.
When To Climb
The best time to climb the mountain is probably in August or September when snow has finally melted off the steep South Face. There is much loose rock on the face and any loose, steep snow would not be a nice thing to have to deal with. If out of season, climbers should be ready and capable of climbing steep snow. Autumn climbing is most certain to entail climbing on fresh, slippery snow.
Camping is allowed just about anywhere. A camp on the mountain massif itself would probably only occur as a forced bivy.