February is one of the busiest times of the year at Yosemite National Park thanks to “firefall,” a natural phenomenon that causes a glowing ribbon of water to look like molten lava cascading down El Capitan’s Horsetail Fall.

Travelers come from around the world to witness the event at the granite monolith, famed for its nearly vertical walls, some booking entry tickets and reserving parking spots a year in advance.

Traditionally, hanging the American flag upside down symbolizes a distress call.

Gavin Carpenter, a maintenance mechanic with Yosemite, spoke to the San Francisco Chronicle on Saturday and said he supplied the flag and helped hang it.

“We’re bringing attention to what’s happening to the parks, which are every American’s properties. It’s super important we take care of them, and we’re losing people here, and it’s not sustainable if we want to keep the parks open.”