- Theatre: Western Europe
- Dates: 16 May 1943
- Location: The Ruhr valley, western Germany
- Outcome: Destruction of two major dams supplying water and power to the Ruhr valley.
- Britain: 617 Squadron of Air Marshal Sir Arthur Harris's RAF Bomber Command, commanded by Wing Commander Guy Gibson
The idea for the Dambusters raid originated in 1940, when aeronautical designer Dr Barnes Wallis calculated the explosive power required to breach the Ruhr dams and discovered that no existing bomber could carry a large enough bomb. However, Wallis realised that smaller bombs accurately positioned at the foot of the dam could have the same effect.
To make this possible, Wallis designed the 'bouncing bomb': a missile that would skip across the water, hit the dam and roll to the bottom. The bomb needed only to be dropped at the right speed, at the right distance from the dam and at the right height above the water. This was the task of the specialist 617 Squadron, formed in March 1943.
Nineteen aircraft took off on 16 May. Nine were to attack the Möhne dam, then proceed to the Eder; five were to attack the Sorpe; and five constituted a 'flying reserve'.
On the outward journey three aircraft were shot down and two damaged. Gibson led the attack on the Möhne dam, which was breached on the fourth attempt, and the Eder, which required only two bombs. Two bombers attacked the Sorpe and a third, driven off course, the Ennerpe dam. Three of the 14 surviving aircraft were lost in the attacks.
The raids flooded mines, factories and houses for 80km (50 miles); over 1,000 people drowned. However, the damage to the Ruhr's industrial capability was relatively minor.
The Dambusters squadron was retained as a specialist precision bombing unit. Gibson was shot down and killed in September 1944; he was only 26.