The alpine meadow greened from the valley floor each spring, one terrace at a time as the snowmelt reached each level. By midsummer even the highest terrace was lush. Then the August heat came — not just warm, but searing — and the thinnest soil dried first. The uppermost terrace, the one with barely an inch of topsoil over granite, went brown while the deeper-rooted terraces below held their green. The autumn rains restored it.