Cholera outbreaks and pandemics
That year, cholera was transmitted along the California, Mormon and Oregon Trails as 6,000 to 12,000 are believed to have died on their way to the California Gold Rush, Utah and Oregon in the cholera years of 1849–1855. It is believed more than 150,000 Americans died during the two pandemics between 1832 and 1849.
Oregon Trail
Reaching the Sierra Nevada before the start of the winter storms was critical for a successful completion of a trip. The most famous failure in that regard was that of the Donner Party, whose members struggled to traverse what is today called Donner Pass, in November 1846. When the last survivor was rescued in April 1847, 33 men, women, and children had died at Donner Lake; with some of the 48 survivors' confessing to having resorted to cannibalism to survive.