Was this because of the angle of your roof? I have most of my roof covered by panels with no such thing. And I’ve seen such ‘blades’ only on houses with relatively steep roof angles to ‘slice up’ ice/snow slabs as they slide off. So, was wondering if there was something different about your situation.
Edit. When I posted that I had no idea I’d posted a few posts above back when or what even a snow guard was, lol.
I’d not think a snow guard like this to keep snow on the roof is a good idea, issues with water backing up as it melts; etc. I like my original idea of something to break up snow ‘slabs’ as they slide off better!
In the past several years we have had some snow slide off as it melts but snow has been dwindling recently. If in a heavy snow area with a path below the roof edge, perhaps an issue, of course! I like the reverse panels I read about where a small amount of power heats them so that they never actually ‘snow’ over.