many days. The next day they added to the flooding by doing the same to dams further upstream on the Roer and the Urft. The river rose at two feet an hour and the valley downstream to the Maas stayed flooded for about two weeks. XXX Corps advanced with heavy fighting along the narrow neck of land between the Meuse and the Waal east of Nijmegen, but Operation Grenade had to be postponed for two weeks when the Germans released the waters from the Roer dams and river levels rose. The U.S. Ninth Army was unable to move and no military actions could proceed across the Roer until the water subsided. During the two weeks of flooding, Hitler forbade Field Marshal Gerd von Rundstedt to withdraw east behind the Rhine, arguing that it would only delay the inevitable fight. Von Rundstedt was ordered to fight where his forces stood. The imposed US standstill allowed German forces to be concentrated against the Anglo-Canadian assault. At first, XXX Corps made rapid progress across most of its front but after the first day, German reinforcements appeared and violent clashes were reported with a regiment of the 6th Parachute Division and armored detachments. Horrocks ordered the 43rd (Wessex) Division to advance past Kleve into the German rear. This resulted in the greatest traffic jam in the history of modern warfare. With only one road available, units of the 43rd, 15th and Canadian divisions became inextricably mixed in a column long. The 15th Division had orders to capture Kleve, but on the night of 9 February they were held up on the outskirts. The 47 Panzer Corps under General Heinrich Freiherr von Lüttwitz was directed to Kleve and the Reichswald. On 11 February the 15th had cleared the town. Having expanded the front line to , the II Canadian Corps, with the 2nd and 3rd Divisions and the 4th Armoured Division, became responsible for the drive along the Rhine to Kalkar and Xanten. XXX Corps was to operate on the right and take Goch before swinging towards the Rhine and linking with the Americans – once Operation Grenade had been launched. The 3rd Division used Buffalo amphibious vehicles to move through the flooded areas; the water rendered the German field defences and minefields ineffective and isolated their units on islands where they could be picked off, one by one. XXX Corps had rehearsed forest warfare