'Fireball' was a British naval minesweeping operation by the reinforced 18th Minesweeping Flotilla in Dutch coastal waters to clear the approaches to the port of Rotterdam on the northern shore of the Waal river’s estuary (March 1945).
In this area, which was vital to the enlargement of the Allies' logistic capabilities in the final months of the war in Europe, the Germans were notably active with aerial minelaying.