This is true. Out West, the sunburn sneaks up on you because the cool air and lack of humidity hides it. You can get dehydrated in a hurry too. Many years ago, while we were still dating, my wife wound up in the ER from dehydration out there after a rafting/fishing trip on the Colorado River - she was feeling a little sick to start the day, and she made the poor decision not to drink anything because she didn't want any bathroom issues while on the water. She didn't mention this decision to me, and I didn't really pay attention, until we got to about 3:00 and she suddenly started having trouble sitting upright. We hustled to the takeout and got there in an hour or two, but by the time we got to the tiny little medical center that poses as an ER up around Leadville, she was in rough shape. She was so dehydrated that they had trouble starting an IV - they couldn't get a vein. We both got fairly sunburned too - I learned a lot that day.
bd