(CNN) — For all the world, it looks like dangerous hot lava streaming down the side of a cliff. But no, that's not volcanic activity in Yosemite National Park in California.
It's water -- a benign and beautiful waterfall experience known as "firefall."
Because of the Covid-19 pandemic and the dramatically growing popularity of firefall, the National Park Service was concerned about crowding around viewing points this year. So it set up travel restrictions and an online reservations system that you need if you want to drive into the popular park. Originally, the firefall "season" was due to end on Wednesday, but because of the high interest, the park has extended the viewing arrangement until Sunday, February 28. Viewing hours are daily from noon to 7 p.m.
So how does 'firefall' happen?
The rays of the setting sun create a pinkish-orange hue at firefall in Yosemite on Wednesday, February 24.
Firefall occurs at Horsetail Fall, which flows over the eastern edge of El Capitan in Yosemite Valley, according to the National Park Service.
It's a small waterfall, and it normally flows only during winter. The Park Service said it's actually easy to miss.
But on some days during mid- to late February, it might glow an enchanting and magical orange when it's backlit by sunset. That gives it that lavalike look.
The Park Service says the dazzling effect happens only on evenings with a clear sky when the waterfall is flowing. Even some haze or a bit of cloudiness can ruin the effect. Mother Nature provides no guarantees.
Firefall is naturally a high-interest topic on Twitter and other social media. Even the US Department of the Interior has gotten in on the excitement posting about it.
Keeping things pristine
It's about a 1.5-mile walk each way from the closest parking to the viewpoint near the El Capitan picnic area.
The park is very serious about crowd control and parking in the ecologically sensitive area, which has been trampled and trashed in the past. The website posts explicit instructions on parking and warns violators could be towed.