Kari Cobb is a Yosemite Park Ranger. She says up to 1,200 people per day were using the Half Dome cables.
"…and that's a lot of people, it causes a lot of gridlock, it causes a lot of people to be stuck in a very uncomfortable and frankly a little bit frightening situation for long periods of time."
Cobb says the overcrowding has contributed to injuries and even deaths.
"People were having accidents, some people were going around the cables, there were unfortunately several deaths on the cables. So all those concerns have forced Yosemite National Park to implement this permit system."
The permits will be available starting March 1st for climbs in May and June.
A $1.50 processing fee will be charged for each one.