Well, I found a whole lot of proof they had lots of snow in the Sierras prior to the January 14, 1907 Jamaica Earthquake:
On January 5, 1907, two miners were trapped in the mountains east of Gardnerville, Nevada, in an abandoned cabin where they had taken refuge from the snowy gales. Chris Jepperson and Jack Reynolds had floundered helplessly in 15-foot drifts, and now they were stranded at an isolated mine. After three days snowbound without food, the men turned to their one possible savior--Jepperson's cocker spaniel. They tied a message around its neck, offered a few encouraging words, and forced the dog out into the drifts to die or reach the town of Gardnerville, about 20 miles away. The heroic canine struggled into town three days later, and then it wandered around for two more days before someone noticed the emergency plea for help. Rescuers trailed the exhausted canine back into the mountains where they found Jepperson and Reynolds unconscious, but still alive.