This Road in Yellowstone National Park Is Melting — but Not Because of the Volcanoes Underneath

Coiling along the Grand Loop trail in Yellowstone National Park, a road called Firehole Lake Drive is melting. Drive through this road and you may notice swirls of steam puffing towards the sky and plants lying dead, burned by bright, hot rainbow waters. Punctuated with simmering geysers, bubbling thermal pools, and blazing hot springs, the road is often buckled up wet into a viscous, ash-colored ooze, per SFGate.

Particularly in summertime, when the Sun above blasts the road with scorching heat and the restless volcanic magma stirring underneath pressurises it from below, the road begins to soften. Each time a car’s tyres roll over this mushy road, they carve out ripples and potholes. The road in Yellowstone is melting, and the culprit can be traced back to a 2014 incident.

The incident was recorded on July 9, 2014, according to a report published by CNN in the same year. The thermal features at Yellowstone, spurred by an active volcano, triggered oil to pour and spill onto the surface of a road, smelting hollows into its asphalt, and digging up holes that spewed billowing white smoke into the skies. The park crew had to close down the road for repair, but when they started the job, they realised it was damaged beyond repair.

The road, Firehole Lake Drive, has to pass through the Lower Geyser Basin that pervades most of this territory. “That’s not a good thing for the asphalt,” Mike Polland, Scientist at Yellowstone Volcano Observatory, explained in a Facebook post shared by USGS Volcanoes. “As it [asphalt] gets heated from below, it’ll start to flow like Silly Putty. And it’s especially bad on hot summer days when the Sun’s beating down on it above. That really causes the asphalt to fail and deform, and when cars drive over it, it gets ripply and potholed,” Poland added.

Calling it an “incredible engineering challenge,” Poland explained that the culprit behind this boiling road is not just the volcanoes sitting underneath Yellowstone’s grounds. This boiling and melting is, though, one of the consequences of the volcanoes' sizzling in the underbelly below. The park, listed as a UNESCO World Heritage Site, is known to sit atop one of the largest chains of volcanoes, which feed the seething waters of more than 10,000 of its thermal features.

When the SFGate reporter spoke to Poland, he recommended against driving through the Firehole Lake Drive, given its bumpiness and vulnerability to melting. “There were a lot of places where it was in bad shape. I was bouncing all over the place,” he recalled. But this is not the only road that features a bumpy head. Many roads in Yellowstone, including dirt roads and rivers, as well as parking lots for the Biscuit Basin and the Sulphur Caldron, are knobbly enough to cause inconvenience to the riders.