Not quite 50 years ago, but close: it was in 1968 or so that Portland psychiatrist H. Clagett Harding, known to his friends as Larry, taught his dachshund to ski. Dr. Harding and his family lived off NW Cumberland, and no snowy winter in Portland was complete with a photograph in the Oregonian of Dr. Harding and Schmalz skiing down a city street in the Northwest hills.
It occurred to me that the Zoobombers might be able to go in for winter sports: it's a bit of a hike from the TriMet Zoo station up to Fairview Boulevard, but then there's a nice downhill with a few challenging turns. Ski MAX? It would be a very Portlandia way to market mass transit.