A freshet is a species of ﬂood—a relatively sudden surge, brought on by heavy rainfall, rapid snowmelt, or the two together, that sends streams and small rivers over their banks. Spate and ﬂush suggest the same phenomenon. Around the term’s usage area—chieﬂy the mountainous Atlantic states and the northern tier of the United States—the deﬁnition of freshet varies locally. In the maritime Northwest, it is as Robert Michael Pyle writes in Wintergreen: “Big, long rains on a warm west wind that really raise the rivers and bring superhigh tides, the two together deeply ﬂooding everything in reach for a few days.” Henry Thoreau, in Walden, speaks of freshets as signs of the inexhaustible vigor of Nature. The word may still be uttered here and there in an older sense, to mean a stream of fresh water, and a related meaning was probably important to nervous European explorers poking at the margins of North America—a region of fresh water beyond the mouth of a seagoing stream.