Complex sentence: A thick, ominous fog obscures everything, reducing trees and buildings to looming shadows, and all communication with the outside world is lost after word reaches them that the eerie weather conditions they face have been encountered by everyone else around the planet as well.
Split into simpler sentences: A thick, ominous fog obscures everything, reducing trees and buildings to looming shadows. Word reaches them that the eerie weather conditions they face have been encountered by everyone else around the planet as well.