Yam Crack is a sharp, focused climb carved into the rugged southwest face of The Bubble, just west of Boulder’s well-loved N Dinosaur Egg formation. This modest but engaging 30-foot crack climb offers a chance to stretch out on solid Flatirons sandstone with a mix of jams and generous face holds on a slightly overhanging, right-leaning line. Though brief, it challenges climbers with a moderate 5.9- rating that edges toward steeper territory, making it an excellent introduction to trad climbing in this iconic Colorado climbing area.

The approach threads through familiar terrain starting at NCAR, following the Mesa Trail south to the Bear Canyon Trail, then climbing north up the gully between the second and third sandstone strata. You’ll find yourself settling into a quiet nook where this route sits unseen on popular topo maps and guidebooks — a hidden gem for those wanting a quick, quality test of crack technique. Since the crack angles right at the top, climbers traverse about 10-15 feet to reach Cold Sweat's anchors, offering solid rappel options with two cold shuts.

Yam Crack’s character is defined by its mix of wide jam placements and smooth, large face holds. While tape protection isn’t necessary, a rack up to #4 Camalots ensures you can protect the slightly overhanging, steeper sections with confidence. The rock quality remains typical of the Flatirons—generally sound but with the usual desert grit, so awareness of foot placements and handholds keeps you safe and efficient on the climb.

This route is a practical choice for climbers looking to warm up on a trad route before heading onto neighboring classics or for anyone eager to add a lesser-known 5.9 crack to their repertoire. Its quick single pitch invites straightforward missions without long approaches or complicated gear setups. Climbing here rewards you with the satisfying feel of ancient sandstone under your fingers and views stretching across the Boulder foothills, where dry winds push against the rock face like a constant reminder of the mountain’s living presence.

Plan to climb Yam Crack during midday or afternoon when the southwest-facing wall basks in sun, warming the stone and offering solid friction. Early season climbs benefit from the warming sun and stable weather patterns typical of late spring through early fall. The approach is straightforward but does involve steady uphill terrain; hikers and climbers should be ready with good boots and enough water for a half-day outing. Cold Sweat anchors provide an easy and reliable rappel descent, allowing safe retreat or quick turnaround.

In all, Yam Crack balances approachable adventure with technical challenge, serving as a strong candidate for climbers hungry to explore the quieter edges of the Flatirons. It’s a direct, no-frills climb that rewards preparedness with fun movement and a brief but invigorating connection to The Bubble’s sandstone walls.