• Local abiotic heterogeneity (via differences in topography and aspect) governs snow 20 accumulation, runoff, and productivity in alpine tundra 21 • Climate warming leads to earlier snowmelt, decreased runoff, and drier soils, potentially 22 decoupling plant resource demand and availability 23 • Topographic position mediates exposure to climate change, highlighting potential 24 vulnerabilities of moisture-limited vegetation patches 25