Their lucky escape comes shortly after US weather body, the National Oceanic and Atmospheric Administration, revealed that at least 21 people died across the United States after they were struck by lightning in the year to date.
Here, Joshua tells the BBC what it feels like to survive a lightning strike:
Joshua White, Austin, Texas:
Me, Colton and our friend Ian, decided we wanted to reach the summit of the tallest mountain in the contiguous United States - Mount Whitney.
We followed a famous backpacking trail in California called the John Muir Trail and for two weeks we were prepping ourselves for our final goal.
On August 14 we made camp in an approach area for the summit called Guitar Lake. We got there in the afternoon and came up against a storm.
There was a lot of rain and hailstones. We had hiked a considerable amount that day and we were pretty shattered but we didn't think we were going to be in a lot of danger.
Then out of nowhere came the brightest light we had ever seen and the loudest noise. We were all thrown around the tent and it was all over very quickly.
We had no idea what had happened at first but quickly realised we had all been struck by lightning.
It was extremely painful. Every nerve ending was hurting and I thought I was on fire. I thought I was going to die. We were all hysterical and shouting for each other to help.
I was trying to rip my clothes off while the other two were trying to do the same.
The whole tent was filled with smoke while smoke was also coming out of our mouths.
We were - to pardon the pun - in shock afterwards.
The force was just so strong. It felt as if we had travelled at high speed and slammed into an unmoveable object. The pain was extraordinary.
I had a burn mark on my shoulder which luckily has gone down thanks to a treatment of aloe vera.
I think it was because I was close to the tent poles and my body was slightly touching them. I think the current passed through me and through to the others. There were scorch marks all over the metal poles although luckily the tent managed to stay together.
We were terrified that it was going to happen again and huddled close together. We just didn't know what to do.
We had a short debate about whether we should go outside but decided we'd stay in the tent. We'd been struck by lightning but we were alive.
Afterwards, when we eventually came out of the tent - other campers nearby came to check on us. They thought we had died.
Our main priority was to get to the bathroom though. We just couldn't believe what had happened to us.
We had to take some time out each to reflect on what had happened.
Afterwards we were wondering what to do about the summit. We still wanted to go - after all we had got this far and just had another few miles to go.
We persevered and we are glad we did but we didn't tell our parents about what had happened until after the fact.