Screaming on Yggsgard?

I'm kinda new to this game. Started playing in December like everyone else, but I only got 6 hours until I had to take a break till January, because of my college's winter break. But now I'm back, playing the game pretty much nonstop, and I'm loving it. But something I've noticed are these weird screams on the Yggsgard map. They're only ever on this map, not in the other Asgard map, just this one. And I'm genuinely at a loss as to what they are. It can't be some Ult that I'm not recognizing, because it's always pretty far away. What are these screams?