Note: as of 2018, the Triad Creek trail has not seen maintenance in well over of a decade and is no longer listed as a trail by the Okanogan-Wenatchee National Forest. However, it does still appear on the most recent USGS maps and for the most part tread is still plain on the ground. Navigation skills and a tolerance for brush and blow-down are required to travel this trail. The rewards are scenic old-growth and access to an isolated section of the Glacier Peak Wilderness unfrequented by human traffic.
The old Triad Creek trail connects Buck Creek Pass to the upper Suiattle River in the remote and little-traveled drainage on the east flanks of Glacier Peak. Access to the trail is from either the Upper Suiattle River Trail and a wild crossing of the Suiattle River (from the west side of the Cascades) or Buck Creek Pass (from the east side of the Cascades). The upper Suiattle River does not have a bridge and the current is usually too strong to ford safely. Logs spanning the river may be found.
From the Suiattle River, the trail begins fairly directly across from where the Upper Suiattle River Trail reaches the riverbed. Much of the east bank has been scraped into bare cliffs. To find the trail ascend where the trees reach the river bed by climbing through steep dense timber and blow-down and veering climbers left. Old tread and log cuts are visible within a couple hundred feet of the river bank and becomes clearer as you climb higher. From the Suiattle River to the crossing of Triad Creek the trail is steep, overgrown, covered in blow-downs, often muddy, and difficult to follow in spots. Persevere and the trail becomes easier with elevation.
After crossing Triad Creek, continue uphill through endless blow-downs on the now easy to follow forested trail. At 2.5 miles from the river (and an elevation of ~5250') you will reach meadows and cross the unnamed creek draining the east side of Buck Creek Pass. Continue uphill through the meadows following bits and pieces of the disintegrating trail if possible. If/when the trail is lost, head straight uphill following the creek toward Helmet Butte with its grassy meadows and characteristic avalanche chutes and veer to your right toward the low point in the pass as it comes into view. If you go straight up the hill toward Helmet Butte you will intersect the middle ridge trail on which you can take a right (heading SE) to get to Buck Creek Pass. If you veer correctly toward the pass you'll meet an intersection of many trails and campsites at Buck Creek Pass.
If you start from Buck Creek Pass, your best course of action may be to follow the main creek drainage downhill through pretty meadows from where the trail starts for approximately a mile until you see the obvious crossing of trail on the bank of the creek.