I don’t know, I think this might be more impressive if it wasn’t just a guy with a hose for a few minutes.
As another commenter pointed out on the video, which is kinda what I was thinking – what about putting this thing on top of a car and giving it sideline wind for several hours with snow, ice and rain?
That might be a little bit better of an indication of what it can do. But it certainly should be able to handle a short rainfall by the indications of this guy-with-a-hose test.