Upon contemplation, all of the trials and tribulations in the movie seem to originate from one thing: parental love. The Ree attack in the beginning which causes the whole expedition to go sour is caused by the chief's drive to rescue his daughter. Glass' entire grueling ordeal in the wilderness and subsequent Roaring Rampage of Revenge is because of his son's murder. Even the bear attack, which caused Glass' wounds and sets the entire premise of the movie into action, happened because Mama Bear was protecting her cubs.
This troper thought perhaps the Hair-Trigger Avalanche was being used as a Chekhov's Gun, until it dawned on him that everything that was going to happen would have happened after the first shots were fired.
