I went in 99 in a May that was colder than average. Peanut butter froze solid and was useless. Corn tortillas disintegrated into corn meal, but flour tortillas stayed soft in extreme cold and so did american cheese. I wouldn't bring any freeze dried stuff again because it was so unappetizing I never ate it. I ran short on sugar drink mix and would bring more. Agree with everyone else about the music (I brough a little am/fm radio. Its light, doesn't use much battery, and reception is good). Also bring some kind of soft lip balm because your lips will get hammered. The rangers use Bag Balm.