Check Out Yosemite’s “Firefall” Illusion Light Up El Capitan

This week, weather conditions at Yosemite were perfect for the annual “firefall”—when the sun strikes the park’s infamous Horsetail Falls at just such an angle to make it look as though the cascading water is on fire.

Yosemite National Park is home to innumerable waterfalls, the longest of which is Yosemite Falls. Horsetail Falls, however, is one of the park’s greatest winter attractions. During mid-to-late February, if conditions are just right, the firefall appears. But, as author and photographer James Kaiser writes on his website, it’s a tricky combination to achieve.

First, the waterfall isn’t always flowing in February; like most of Yosemite’s waterfalls, it’s fed by snowmelt. If there isn’t enough snow on the mountain, or if the weather doesn’t grow warm enough to melt the snow pack, Horsetail Falls will be dry, notes Kaiser, who wrote the book Yosemite: The Complete Guide.

The weather also plays an important role. If the sun’s rays can’t penetrate cloud cover to reflect off Horsetail Falls, then nothing will happen. It must be a relatively cloud-free evening for the firefall effect to be visible.

And even if all the conditions are perfect, the effect only lasts for about 10 minutes at sunset. When the sun moves into position, allowing its light to bounce off the falling water, the stream becomes illuminated for the nearly 1,570 feet it plunges down the side of El Capitan. And the illusion is especially spectacular this year. “The waterfall is bigger than it has been in a long time due to all the rain and snow we have received," Scott Gediman of the National Park Service said to Amanda Jackson at CNN.

Stunning time lapse video captures a rare 'firefall' at Horsetail Fall at Yosemite National Park. https://t.co/80cC6xdbHY pic.twitter.com/D8GODz7due

— ABC News (@ABC) February 16, 2017

The firefall has grown in popularity in recent years among spectators and photographers set on capturing the firefall. It usually starts around 15 minutes before sunset, but Sangeeta Dey, a National Geographic photographer, recommends arriving by 11 a.m. to claim your spot. “Bring a chair, plenty of snacks, water, and warm clothes to keep you comfortable,” Dey tells National Geographic Australia. “I saw people who were so miserable standing there feeling cold and hungry that they just wanted to get this over with. Don’t be that person.”

Yosemite National Park used to create an artificial firefall tourist attraction, reports Talia Avakian at Travel + Leisure. In the 1800s, they pushed the ashes left over from camp fires off the edge of a cliff to create a similar firefall illusion. This practice was eventually discontinued after the hotel that hosted the event was damaged by heavy snowpack and then lost in a fire.

As Avakian notes, the natural firefall keeps the tradition alive today. People travel from all over the world to experience the illusion. Though it may be too late to catch this year’s event, it’s never to early to plan for 2018.

Check out the fiery​ illusion in full: