Farzil ice phenomenon happens when surface water losses heat swiftly and water is supercooled. Due to this the surface water turns to ice and the small ice size along with the current end up at the bottom. The crystallisation continues to form highly dense ice crystals.
Similar is what happened in the video. The frazil ice formation is clearly seen, as the flowing water turns to ice quickly in the video. This video was shot by Brad Atchison in Squamish, BC, Canada.
As the peak of winter is underway, such occurrences are not surprising. Canada receives heavy winter as most of Canada is under a blanket of snow.