Suppressors Omega at high altitude

[Conrad101st]

So was at 11,100 feet shooting my 300 win mag with the omega attached. It was MUCH louder than at my home elevation of 975 feet. Almost didn’t sound suppressed. I was shooting in a canyon about 1 mile across so that be part of it but suspect it may the significant decrease in air pressure. Any thoughts??

 

[Mordamer]

Was there any kind of large object in front of the suppressor that could reflect sound back at you? This makes the shot WAY louder. To test this, shoot at a dirt berm from 100 yards and then shoot at it from 10 ft. If there was a large tree trunk or something similar more or less in front of the muzzle it could cause a lot of sound to reflect back. Just one possibillity out of many.

 

[2ndamendfan]

At 11,000 ft the air is 33% less dense (same temp, humidity not withstanding) I would think less dense air would transmit sound worse, not better. (No air in space = no sound). Less air molecules and the space between them is greater.