Showing my age ...paid $69 for largest thermarest back in the mid 1990s and used it in CO every year for 6-7 years with no problem at 10,000'. It stands-full blown- behind the door in the den @ 72 degrees. Last used 2002.
Hope the 4 Y.O. G.D. grows up quick so we can all go after ELK one time before I pass it all to her.
Added: Randy, got that type from Army-Navy store here and have not needed it yet, but it is in the trailer, along with another 1,000 lb of junk.
Will take it for that Emergency Over Night Stay @11,000" when I go that direction or under the T-rest pad if we ever camp again.