Late Friday night Grand Canyon National Park rangers received word that a 19 year-old male hiker had gotten injured in a rock fall that occured in an area of the canyon known as the "Box".
The incident happened during a thunderstorm in the steep canyon approximately nine miles below the North Rim on the North Kaibab Trail.
The man was brought to Phantom Ranch by fellow hikers. Park rangers responded and immediately began to provide medical treatment.
Rangers requested a helicopter for transport, but due to weather it was unable to respond until Saturday morning.
The patient was transported in critical condition to the Flagstaff Medical Center by Guardian air ambulance at approximately 6:00 a.m.
The weather forecast calls for additional thunderstorms in the Grand Canyon area over the next several days.
Hikers are advised to be especially cautious during storm activity and should take precautions based on the areas they are hiking in, as well as weather conditions.