Boulder Brook Loop

Boulder Brook Loop is an 8.6-mile circuit from Storm Pass: climb beside Boulder Brook, cross the North Longs Peak corridor, and return past Alberta Falls. Give it about five hours and expect a hard, high-altitude hike with about 1,510 feet of gain and a high point near 10,310 feet. Pets aren't allowed on Rocky Mountain trails. Want a shorter taste? The Boulder Brook campsites are 2.8 miles one way from Storm Pass; turning there makes a 5.6-mile out-and-back, not this loop.

The trailhead is a tiny pullout on Bear Lake Road with room for about four or five cars. If it's full, use another established lot or the park shuttle when available; don't park along the road. The route starts across a grassy meadow and crosses Glacier Creek within the first 100 yards. Pass the Sprague Lake junction around a third of a mile in; at the next Glacier Creek junction, around half a mile, continue straight for Boulder Brook.

This is the hardest stretch: one roughly 0.4-mile section climbs at grades over 20%. Cascades and three footbridges break up the ascent. Near 1.7 miles, the canopy thins and Longs Peak and the Continental Divide open up. Boulder Brook drains from Boulder Field below Longs Peak into Glacier Creek near Sprague Lake. At about 2.6 miles, turn right onto North Longs Peak Trail to make the loop; the left branch continues toward Granite Pass.

North Longs Peak descends past occasional mountain views. Around 4.75 miles, cross Glacier Creek beside a small gorge; the route then joins a busier path past Alberta Falls at about 5.7 miles before Glacier Creek Trail leads back through aspen and pine to Storm Pass. The brook cascades and the falls are the standout water-and-rock views, so step aside from the tread if you stop for photos.