In February 1941 bad weather limited Sperrle to 975 bombing operations. Bomber wings under Sperrle's command struck at Swansea. 101 high explosive and several hundred of other types of bombs were dropped disrupting the Great Western Line. In March the intensy of bmbing operations increased, "Luftflotte" 3 flew 2,650 operations. Attacks against Cardiff in March 1941 caused some of populace to evacuate the city, a phenomenon known as "trekking". Such incidents caused only temporary drops in morale. Other bombing operations were carried out against Liverpool by 316 aircraft, Glasgow by 236, Bristol by 162 bombers, London by 479 aircraft Portsmouth by 238 and Plymouth over two nights by 125 and 168 bombers.