The Krimmler Ache is a glacial stream whose flow varies greatly with season. The flow in June and July is 20000 m³/h (about 5.28 million gallons per hour), while in February it is only 500 m³/h (about 0.13 million gallons per hour). The greatest measured flow was on 25 August 1987, when it was 600000 m³/h, or almost 160 million gallons per hour.