If you are in the White Mountains of Arizona and ask for the nearest ﬂume, you will be shown a water pipe or trough. In New Hampshire’s White Mountains with the same request, helpful locals will take you to a ravine. Thus, ﬂume seekers should know which White Mountains they’re in. Flume refers to both artiﬁcial and natural water channels. A westerner’s ﬂume is usually the engineered one, an inclined chute or pipe built to carry water for irrigation, mining, and other uses. Easterners refer to the geomorphic ﬂume, a steep-sided ravine with a stream that descends in a series of cascades. New Hampshire’s famous ﬂumes, which formed when water eroded a dike of basalt or soft rock, unplugging ﬁssures in harder rock, include Crawford Notch, Sabbaday Falls, and The Flume at Franconia. Flowing mountain water stair-steps down these chasms, smoothing granite streambeds and plunging into spring-clear pools.