Saw these on a trip to the Harrisburg area of Pennsylvania.
They keep built up snow and ice from sliding off of the roof and injuring people. You’ll usually see them on roofing near or overhanging walkways and sidewalks.
Snow guards or snow stops. They keep the snow from dumping off the roof quickly.
idk if this is the same, but in my country we have things looking like tiny ladders standing on their side in exactly that location on roofs to stop a big load of snow going down at once, possibly hurting someone unsuspecting standing below
yeah that’s it. i researched the name in my country and translated it to “snow guard”: https://images.app.goo.gl/KmfEtxJa3CjDwkCg9