the 1st of December noon
From this time forward thick darkness set in , and the cold became intense . The thermometer fell _ below _ zero , and after that they never saw it _ above _ that point for months together -- 20 degrees , 30 degrees , and 40 degrees below were common temperatures . The ice around them was ten feet thick . On the 1st of December noon was so dark that they could not see fifty yards ahead , and on the 15th the fingers could not be counted a foot from the eyes . The thermometer stood at 40 degrees below zero . The darkness could not now become greater , but the cold still continued to grow more intense . It almost doubled in severity .