In the characteristically temperate Bay Area, snow rarely falls along the ridges of the GGNRA. But in 1976, the Marin Headlands and Mt. Tamalpais, and even some San Francisco park sites like Lands End and Sutro Heights, were dusted with a light layer of snow—truly a once-in-a-lifetime scene to behold. Thank you to Dennis O'Rorke for preserving this ephemeral event in these photos he took that day around the parks.