Sound from High Altitude?

Recalling once reading in a book on Ballooning (the Double Eagle Two or another famous Balloon Flight), -about how in the Stillness of the Night, -you can clearly hear People talking, Dogs Barking, etc, -thousands of feet below! -I'm wondering how useful this might be to someone in a Search and Rescue (SAR) situation. Particularly if you're located in an area with some Heights above you. (though the Greenery of the Forest may muffle some of this down). One can devote some of their Efforts to Calling, Whistling, etc Upward. Towards possible Rescuers etc.

Along this same line, -I've once known someone in the Service at the Presidio, (San Fran / Monterrey area), -who could well hear the Barking of the many Seals down on the Beach or Rocks below, -from the Heights well Above!,... [color:"black"] [/color] [email]ScottRezaLogan[/email]

I know that you can hear sounds further when it's foggy, apparently due to the moisture in the air.

I wouldn't be surprised if you could hear things from a hot air balloon, esp if it was isolated. We are usually surrounded by so much noise that we don't even hear, it forms a kind of white noise and limits what else we can hear.

Sue

It is true - on my one flight last fall, it is extremely still in the basket, and we were able to hear dogs barking and bird hunters (shotguns) for a wide radius. I'm sure we'd have been able to hear someone yelling at us within some radius, but this did not happen.

On the other hand, the balloon path is quite limited, and you don't get to go around for another try.

I think you are mistaking how well sounds carry in still air for some other phenomenon. Balloons only go out when the winds are very, very light so that qualifies as still air.

I've camped on ridgetops above treeline and heard people talking and dogs barking 2000' below - very still night.

I've also camped in the valley below ridgetops where the wind howling sounded like jet engines up on the ridge. Had to wear earplugs to sleep that night.

I've tried using a rescue whistle to signal in snow and also in trees and found the useful distance quite short and even shorter if there is wind noise to ruin the signal-to-noise ratio.

So, my summary is, don't count on altitude having any helpful effect to signalling distance. Stillness helps, wind and sound absorbers in the path don't.

Unimogbert