In late February 1945 the Ninth Army launched Operation Grenade, which was the southern prong of a pincer attack coordinated with Canadian First Army's Operation Veritable, with the purpose of closing the front up to the Rhine. By 10 March, the Rhine had been reached in all sectors of Ninth Army's front. It was not until after 20 March that Ninth Army units first crossed the Rhine itself (Operation Flashpoint). However, after doing so, the Army quickly struck east around the north of the Ruhr. An enormous pocket soon formed containing the German Army Group B under Walter Model. By 4 April, Ninth Army had reached the Weser and was switched back to 12th Army Group.