According to the National Park Service (NPS), officials received a report of multiple people struck by lightning at the Bright Angel Trailhead just before 3 p.m. on July 20.
Crews responding to the scene found a 30-year-old man and 28-year-old woman unresponsive, however, the man regained consciousness without medical assistance.
Life-saving measures were performed on the woman and she regained a pulse.
Due to storm activity, air transport was not available and the victims were transported by ground to the Flagstaff Medical Center.
The woman is currently in critical condition at a burn center in Phoenix.
At least two other people suffered "lightning splash injuries" and were treated at the Grand Canyon Clinic.
"The lightning strike is a reminder that monsoon season brings not only rain, but dangerous and potentially life-threatening lightning during thunderstorms," officials said on Wednesday. "Serious injuries and fatalities have occurred at Grand Canyon National Park as a result of lightning strikes. Visitors to the park are reminded that if the sound of thunder follows a lightning flash within 30 seconds or less, they should seek shelter in a building or vehicle or proceed to the nearest bus stop to get on a park shuttle."
Officials say to stay clear of the rim and metal fencing if you're not around anywhere to take shelter in.
Officials say lightning strikes an average of 25,000 times per year in Grand Canyon National Park.
Kaitlyn Thomas with NPS says, "It was definitely a scary moment for everyone involved."
Jessica Walker was at Mather Point with her family when the storm hit. She said it was sunny with some overcast and in a matter of minutes, the storm rolled in.
She and her family immediately went inside for shelter.
"It rained harder than I have ever seen it rain, anywhere really," she said. "There was lightning literally across the sidewalk from where we were standing outside."
Adding, "It was very loud and crazy. I have never experienced lightning like that."
Lightning flashes the cliffs and buttes of Grand Canyon. (Grand Canyon National Park Service)
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