So, I froze my camelback over night for an Adventure Race. It was 87 degrees and very humid. I wish I had left room in it to add some water in the morning.

There were several times throughout the race I couldn't get water because it was STILL frozen! Even after 8 hours of racing in the sun on the beach. Fortunately they had set up aid stations with water--which they don't normally do for an AR.

Next time I will only fill it 1/2 way before I freeze it.