Complex sentence: When the 103rd Division moved back to prepared lines in the Hagenau Forest on January 20th, the battalion withdrew alongside them; the weather conditions, however, proved to be unfavourable to the towed guns, and several had to be abandoned and destroyed in situ.
Split into simpler sentences: When the 103rd Division moved back to prepared lines in the Hagenau Forest on January 20th, the battalion withdrew alongside them. Weather conditions, however, proved to be unfavorable to the towed guns, and several had to be abandoned and destroyed in situ.