Hebgen Lake

Overview

Hebgen Lake is the Madison River's first stop after it leaves Yellowstone National Park, a reservoir a short drive west of West Yellowstone that FWP lists at 12,563 acres and 6,538 feet, held back by Hebgen Dam, which NorthWestern Energy operates to regulate flows into the river below. The Madison enters at the head of the long, narrow Madison Arm; Grayling Creek, Duck Creek and the South Fork Madison feed the other arms; and everything leaves through the dam into Quake Lake and the famous river beyond. The 1959 earthquake, magnitude 7.3 by the USGS, tilted the basin and sent seiche waves over the dam, but the killing landslide was downstream in the Madison Canyon, where it buried a campground and dammed the river to create Earthquake Lake. Hebgen itself is a weedy lake of broad flats, only about 70 feet at its deepest, and that is the point: the flats of the Madison and Grayling arms and the west shore grow the mayflies that make this the best known gulper fishery in the country. From mid-July into September, rainbows and browns cruise the surface on calm mornings eating Callibaetis and, earlier in the day, tiny Tricos, and they are sight-fished one rise at a time until the wind comes up. There is no salmonfly hatch here; that is a river event on the Madison. Before the gulpers, the lake fishes with midges and early Callibaetis after ice-off, streamers along the receding ice, and chironomids under indicators; after them, fall is streamer time as browns stage in the Madison Arm before running upriver to spawn.