The Grand Fleet sortied in response to an attack by German ships on British light forces near Dogger Bank on 10 February 1916, but it was recalled two days later when it became clear that no German ships larger than a destroyer were involved. The fleet departed for a cruise in the North Sea on 26 February; Jellicoe had intended to use the Harwich Force to sweep the Heligoland Bight, but bad weather prevented operations in the southern North Sea. As a result, the operation was confined to the northern end of the sea. Another sweep began on 6 March, but had to be abandoned the following day as the weather grew too severe for the escorting destroyers. On the night of 25 March, "Thunderer" and the rest of the fleet sailed from Scapa Flow to support Beatty's battlecruisers and other light forces raiding the German Zeppelin base at Tondern. By the time the Grand Fleet approached the area on 26 March, the British and German forces had already disengaged and a strong gale threatened the light craft, so the fleet was ordered to return to base. On 21 April, the Grand Fleet conducted a demonstration off Horns Reef to distract the Germans while the Imperial Russian Navy relaid its defensive minefields in the Baltic Sea. The fleet returned to Scapa Flow on 24 April and refuelled before proceeding south in response to intelligence reports that the Germans were about to launch a raid on Lowestoft, but only arrived in the area after the Germans had withdrawn. On 2–4 May, the fleet conducted another demonstration off Horns Reef to keep German attention focused on the North Sea.