Our witness grew up in the Yukon and spent years on hunting trips in the bush. In the early 2000s, while living in southern BC, our witness drove north with a girlfriend to visit family in Whitehorse, and the two took a day trip to Atlin, a tiny town on Atlin Lake just south of the Yukon border, surrounded by wilderness.
After a soak in some small warm springs off an old mining road, the couple drove further and found a spur road ending in a pullout where hunters unload ATVs. A narrow trail climbed through the forest up the mountain, and they set off to stretch their legs.
The usual birds and squirrels were calling, and then the forest went completely silent. Moments later it was split by the loudest, most aggressive scream either of them had ever heard. It sounded animal but also disturbingly human, like someone shrieking with rage at the top of their lungs.
They looked at each other and walked as fast as they could back to the vehicle, then sat watching the trees for a minute to see whether anything had followed. Nothing came, and they drove away shaking. They hadn't seen another person or vehicle all day, there are no cougars that far north, and the lifelong Yukon hunter knows what a bear sounds like. Whatever screamed, it wasn't one of those.