Oregon Hikers

While camped on the PCT near South Sister on 9/1, I heard a series of explosions coming from up on the mountain. It was not gunfire. The explosions sounded timed, almost evenly spaced. Definitely not the time of year for avalanche control, I would think. Not much snow to be seen...

Did you see any dust clouds drifting across the landscape nearby or in the distance? I'd expect that during the dry season.

Locating sounds in the mountains are tricky due to distance and reflections (echoes). I doubt that they came from within the wilderness boundary. My guess is it was related to road work somewhere.

Hard to say, there was a lot of haze from the wildfires in California.

The South Sister's bulging seems to have calmed down in recent years but you never know. If the bulging had anything to do with the explosions, it probably would have shown up on someone's seismograph.