Answer:
They faced starvation and disease. A lot worse then it sounds, medicine was very bad back then and starvation was ramapant. Also homocidal radicalized Mormons. Some groups of mormons were ultra-violent and the US military even waged a war aginst on of these crazy cult religious sects once. In the infamous Mountain Meadows Massacre a group of mormons killed hundreds of frontier men, woman, and children. Starvation and disease are by far the most common cause of death, mormons were not as common. Native Americans were massacred by settlers, but not the ot way around.