Aniakchak River Professional Review and Guide
"For remote wilderness, solitude, wild weather, and wilder water, a float trip down the Aniakchak is very special. But don't attempt it unless you are an expert paddler, extremely self-reliant in Alaska wilderness camping, and ready for severe weather and self-rescue. Aniakchak National Monument and Preserve is one of the least visited national park units in the U.S. Issuing forth from cerulean Surprise Lake in the heart of the Aniakchak Caldera, the Aniakchak is truly a wild river.
After 1 quiet mile, the river quickens and plunges through The Gates, a narrow 1,200-foot-high gap in the crater, dropping an average of 70 feet per mile through frothy, rocky Class II, III, and IV turbulence for about 15 miles. Then it slows to Class I and meanders 17 miles to Aniakchak Bay."