Mount Whitney is the highest peak in the U.S. outside of Alaska.
Tyler Armstrong made it to the top of the 14,505-foot mountain with his dad on Wednesday.
"My favorite part of the hike was when I got to the top, and the snow looked like, when I looked up, I can see everything on top," he said.
Armstrong suffered some slight altitude sickness and got a minor cut on his knee coming down, but he was otherwise fine.
