Plague Boys on the Lower Infirmary Slabs demands more than brute strength—this one rewards climbers who read the rock and trust delicate footwork on subtle slabs. Located within the South Fork of St. Vrain Canyon near Lyons, Colorado, the route carves a quiet line across rounded, sun-warmed granite faces. From the ground, the climb appears approachable, but the rating of 5.8 hides a demanding balance act that can surprise even experienced climbers.

The approach through St. Vrain Canyons unfolds in pine-shaded terrain where the air carries a hint of mountain sage and pine resin. Hiking in, you’ll notice the serene flow of the South Fork—a constant reminder of nature’s pulse just beyond the rocks. The route itself begins with a slab climb heading toward the first bolt, positioned notably high, giving a sense of exposure that challenges confidence. From this bolt, you angle right to by-pass the second bolt and follow a series of rounded ribs leading into a left-leaning corner that demands precise fingertip placements. This corner section is where the climb settles into its groove—technical but forgiving, asking for steady moves rather than explosive ones.

Protection calls for sport climbing gear: quickdraws are essential for the bolts, with a top rope anchor established at the two-bolt chain system perched above the final short overhanging move. Experienced climbers often pack a yellow Metolius (#2) for securing the space between bolts, alongside smaller cams like Friends #1.5 to #2 or Black Diamond #0.75 to cover the crack in the corner. This blend of fixed and trad protection offers a safety net without interrupting the rhythm of the route.

Given the slabby nature and reliance on friction, sturdy climbing shoes with sticky rubber are crucial. Early morning or late afternoon attempts benefit from cooler temperatures and reduced glare, as the sun’s angle can turn the rock into a heated slab that tests your focus and foot sensitivity. Avoid climbing late in the day during higher sun exposure to prevent overheating and slipping risks.

Plague Boys is an excellent choice for climbers looking to sharpen their slab skills in an environment that feels removed from busier crags. While it’s not a lengthy climb—one pitch covers the entire line—it offers a rich learning experience with its nuanced moves and thoughtful gear placements. The shared anchors allow for safe top rope sessions, ideal for practicing footwork under controlled conditions.

Access to the Lower Infirmary Slabs is straightforward, with a short hike from the South Fork trailhead. The slabs rise cleanly above the forest floor, their warm granite inviting careful exploration. Climbers are advised to hold tight to their balance on this climb’s understated but real challenges—Plague Boys might just rewrite your expectations about what a 5.8 can demand.