As someone who lives in a high altitude desert climate (6,040 ft above sea level, in the Rockies of Colorado), and who often travels up and down the mountains with a pipe, I can tell you that I never felt any effects from altitude. Things like air humidity, weather conditions, type of pipe, packing, etc, are much more important. This is, of course, my opinion. I'm also a guy that smokes any blend without drying it (on the contrary, I take great care to prevent it from drying below the level it is when the tin is first opened) and have no issues with St. Bruno. Actually, the older St. Bruno used to be even more moist than it is today, and I never had problems with it then, either.