One of the most familiar images of Yosemite National Park… is Half Dome, the park’s tallest granite peak--- at nearly 5,000 feet.

It’s popular with hikers, and while it is a 10-hour trek, and not for the meek, a climb here requires no special expertise.

And while thousands may have made the trek with nothing but some sore leg muscles to show for it, clear warnings are posted that a climb here could be deadly, because Half Dome is a gigantic natural lightning rod.

On July 27th, 1985, five men set out to climb Half Dome.

Adrian Esteban was one of the hikers.

ADRIAN ESTABAN: “It was predominantly a blue sky with just one little cloud way off in the background. We’re hiking along and we get about to the half way point and we noticed the cloud was getting closer into the valley and now it’s getting darker and darker.”

But he says the excitement of the storm actually drove them to try to finish their goal.

A single thunderstorm can contain more energy than ten atomic bombs.

And lightning strikes, on average, killed more than 40 people each year in the United States between 2000 and 2009.

By 6pm, despite the storm, Adrian Esteban and his friends reach the summit.

Their showdown with Yosemite seems to have gone their way.

But the storm is just beginning to slam into Half Dome. Escape is impossible.

Desperate, they seek shelter in a rock enclosure, but it’s too late.

ADRIAN ESTABAN: “I felt my skin tingling. I felt like my hair was standing on end. And that’s when the lightning bolts hit.”

The summit took a direct hit.

Millions of volts of electricity arc over the wet stone surface—into the rock enclosure.

The lightning strike kills two of Adrian’s friends.

Two others suffer massive internal injuries along with third degree burns, and they take years to heal.

Adrian was in motion when the lightning struck. Because little of his body was in contact with the rock, he did not ground the lightning’s electrical charge, and he escaped with minor injuries.

ADRIAN ESTABAN: “And I just want to impress on people the dangers of nature, how strong, how unpredictable it can be.”

A hike on Half Dome can be an exhilarating experience for those who decide to make the trip.

But, it is important to respect nature, and like the caution signs warn: don’t climb this granite peak if a thunderstorm is anywhere in the horizon.