After weeks of waiting, visitors to Yosemite National Park were treated to a fiery spectacle this weekend. When the conditions in California’s Yosemite Valley are just right, the sun rises behind Horsetail Falls, one of the park’s marquee cascades. When that happens, the falls light up as if on fire. 

This “firefall” is a stunning optical illusion that draws thousands to the park each year. The red color of the falls has to do with the wavelength of the light as it stretches across the horizon early in the morning. This is similar to the phenomena that causes red sunsets and morning alpenglow. 

“When the sun drops at the exact right angle, it reflects upon El Capitan,” Yosemite National Park public affairs officer Scott Gediman told French media outlet Agence France-Presse. “It’s a combination of the sun reflecting on the water, clear skies and water flowing.”

The stunning visuals are so popular that Yosemite has been forced to impose visitor restrictions this time of year. Otherwise, the crowding could negatively impact the trails from which the firefall is visible. As of 2023, anyone planning to visit the park during the last three weeks of February will have to make an advance reservation to secure entry to the park. Those looking to stay in Yosemite’s campgrounds will need to request appointments as well. 

Despite the red tape, plenty of photographers flocked to the park this weekend to capture the firefall in action.

“The pictures I’ve seen are just gorgeous,” Fresno’s Terry Cantrell told the New York Post. “Everybody wants to have their own, so this is what I’m trying to do.”

Peak firefall season is just about over, so if you’re planning on seeing it yourself, make a weekend reservation ASAP, or plan a weekday visit. February isn’t over yet—and the falls could put on another stunning show just in time for you to see it.