On the rugged face of the Flatirons just outside Boulder, Colorado, L.A.S.T. aka Unknown Flakes stands as a compelling challenge for trad climbers ready to trust their gear and read the rock. The route begins just right of the Stainless Steel Rete, where a striking left-facing flake system arcs upward, daring you into a sequence of precise moves and thoughtful protection. Early on, you'll navigate a mini roof—brief but technical, requiring small wires that test your gear placements and nerve. The crux blends technique with a touch of boldness, as some sections stretch protection, earning the route its PG13 rating.

From this point, the climb fans left along a series of flakes rated around 5.7 or less, peppered with small cams and nuts, ending at a ledge that breathes relief and assessment. The rock here is solid but not forgiving, demanding clean placements and careful movement. Beyond the ledge, the route bends up and left once more, following a flaring seam requiring steady feet and calm hands to reach the cliff top.

The scene is classic Colorado granite—textured and confident under your touch, with intermittent horns and edges presenting challenging but rewarding protection opportunities. Several two-foot slings are invaluable for securing around flares and horns, though some anchor points, like the sling on the horn, offer less-than-ideal safety and highlight the need for vigilance.

Once on the summit, the descent calls for respect and caution. Belay at the top, then downclimb right to reach the cold-shut rappel station at Zimbra’s anchors. This descent requires a careful approach as terrain is exposed and variable.

For climbers seeking a single-pitch excursion with focused trad moves and a taste of Boulder’s classic granite features, L.A.S.T. delivers an experience loaded with character and technical demands. It's not for beginners, as runouts and tricky placements test leadership confidence and gear skills. Hydrate well, set off early to avoid afternoon heat on this west-facing wall, and bring a rack heavy on small cams and nuts. Boulder’s stingy granite rewards precision and patience, offering climbers a chance to engage deeply with the rock.

Wildlife, whispering fir and ponderosa pines frame the approach, while sunlight warms the cliff face, inviting steady hands and sharp focus. The sense of place is immediate, sharp with the scent of pine and earth, solid granite beneath your fingertips challenging every foothold. This is trad climbing stripped to essentials—gear, skill, and a smidge of courage—woven into an 80-foot line of subtly complex moves. Prepare, protect, and push upward—the flakes await.