In The Indifferent Stars Above, the Sierra Nevada mountains, whose name translates from Spanish as “Snowy Mountains,” are a fierce geographic obstacle that critically shaped the fate of the Donner Party. With peaks ranging from 11,000 to 14,000 feet and rugged terrain, these mountains posed a daunting challenge for the pioneers taking the California Trail. The Donner Party’s late-season travel through the Sierra Nevada had catastrophic consequences. The range’s eastern face, formed by the uplift of a massive granite block, features steep gradients and complex topography. This geological characteristic, coupled with harsh winter snowstorms beginning in October 1846, trapped the party in deep snow and freezing temperatures, preventing them from crossing the summit into California with their wagons and forcing them to establish camp.

Before reaching the Sierra Nevada, the party had opted for Hastings Cutoff, a supposed shortcut intended to abridge their journey by 300 miles. However, this route led them through some of the most inhospitable terrain of the Great Basin, including the nearly impassable Wasatch Mountains and the arid Utah Salt Flats, notorious for their lack of water. By the time the party rejoined the traditional California Trail in late September, they were severely delayed, frantically racing against the weather to cross the Sierra Nevada.