Complex sentence: The terrain and heavy rain, however, prevented deployment of tanks and anti-tank guns so the infantry for the time being were on their own so facilitating the 15th Panzer Division's counter-attack on 22 March to recapture much of the bridgehead.
Split into simpler sentences: The terrain and heavy rain, however, prevented deployment of tanks and anti-tank guns so the infantry for the time being were on their own. Sure enough 15th Panzer Division's counter-attack on 22 March recaptured much of the bridgehead.