The Winter of 1861-62 was one of the coldest, perhaps the coldest in the history of the West. It was also the the first winter of the Civil War.

The winter weather of 1861-62 proved to be cold and dangerous on the Mullan road and its environs. One of the most dramatic events in the Mullan Report is the story of the man who was caught that winter in a blizzard, suffered frostbite, and lost both of his legs. Deep snow and frigid temperatures covered the entire Pacific Coast region while heavy rains over snow caused flooding in Oregon and severe flooding in central and southern California.

The northwest snow was powdery and soft, bringing transportation to a halt. Snowshoes sank through the surface, and wagons could not be pulled through it. Many horses and cattle died from starvation when they could not dig through the snow to find grass.

The difficult traveling conditions meant that supplies rapidly became scarce. As food became more difficult to find, the commodity prices escalated rapidly, especially in nearby mining camps. Many of the miners in the area refused to leave their claims, and some starved to death before the weather broke and supplies finally arrived.