The Sierra crossing involved extreme temperature and elevation swings in one day

Evidence

In a few hours the mercury had fallen from 103° to 29°, and we had ascended 6,987 feet in 105 miles! After passing through the sheds, we had several grand views of a pine forest on fire before reaching Truckee at 11 p.m., having traveled 258 miles. — Isabella L. Bird, A Lady’s Life in the Rocky Mountains, 25