Snowfall is an important part of Donner Summit history. It affected the emigrants. The Donner Party was caught by it. The railroad had to overcome it. The snowpack closed the Sierra for months until the highway was cleared in winters beginning in 1932. Annually merchants on the eastern side anxiously awaited snowmelt so tourists would arrive. They even tried to hurry Mother Nature by holding snowshoveling bees, spreading soot, and holding contests for the first auto of the season. The first bicyclists to cross the Sierra, the first motorcyclist to cross the Sierra, and hte first "autoist" (to use an histoirc term) all fought the snow, having no idea there could be so much. The first two resorted to the snowsheds to travel. Those sheds, the iconic image of Donner Summit, were built of course because the railraod builders had no idea there could be so much snow - an annual average of 34 feet.
The annual compilation to make the chart above is done by Randall Osterhuber of the Central Sierra Snowlab in Soda Springs. Click for a full size version in PDF format- about 5 meg.