On the morning of 8 April 1940 "Glowworm" was on her way to rejoin "Renown" when she encountered the German destroyers and in the heavy fog before 8:00 a.m. The destroyers were part of a German naval detachment, led by the heavy cruiser , on its way to land troops at Trondheim as part of the German invasion of Norway ("Operation Weserübung"). "Glowworm" opened fire and the German destroyers attempted to disengage, signalling for help. The request was soon answered by "Admiral Hipper" which spotted "Glowworm" at 09:50. "Hipper" initially had difficulty in distinguishing "Glowworm" from "von Arnim", but opened fire eight minutes later at a range of with her main guns. "Glowworm" was hit by "Hipper"s fourth salvo and she started making smoke. She turned into her own smoke in an attempt to break visual contact with "Hipper", but the cruiser's radar-directed guns were not affected by the smoke. When the destroyer emerged from her smoke the range was now short enough that the cruiser's guns could fire. "Glowworm"s radio room, bridge, and forward 4.7-inch gun were all destroyed, and she received additional hits in the engine room, the captain's day cabin, and finally the mast. As this crashed down, it caused a short circuit of the wiring, causing the ship's siren to start a banshee wail.