Rime Ice Rivers: How many ways can water flow down a mountain?

Two years ago, I joined a couple of friends on a climbing trip to Mount Shasta. We failed to summit due to high early morning winds, and turned around at sunrise when we noticed no climbers above us were advancing to the windblown ridge. On the way down, we encountered incredibly beautiful rime ice rivers, coursing down the steepest part of the route, pushed by the incessant downslope wind.

Rime ice coating the rocks the day before.