A 60-metre stretch of road in Santa Clarita, California rose up off the ground and crumbled in the space of about 3.5 hours on Thursday 10 November, with further buckling reported over the next few days.
Some parts of the road are now completely cracked and unusable, while others have risen more than 4.5 metres (15 feet) above the ground, but no one's quite sure what caused such a dramatic shift. When roads buckle like this, it's usually due to serious shifts in the earth below caused by earthquakes or serious rainstorms, but geologists have already ruled out these possibilities.
"There was no big rainstorm that triggered this. There was no big earthquake that triggered this," University of California, Los Angeles geologist Jeremy Boyce told CBS news.
Boyce took the opportunity to get his students out on the field to see a rare example of how geological events can happen surprisingly quickly - turns out Earth's bits and pieces don't always move at a glacial pace.
"When we think about geology, we think about processes that happen over millions and billions of years, so the opportunity to bring students out and see something happening over a scale of hours gives them the idea that not only does geology take forever, it can also happen almost instantaneously," he said.
#UPDATE: Vasquez Canyon Rd still rising. Road now closed between Lost Creek Rd & Vasquez Way https://t.co/gcHQaXtLJI pic.twitter.com/LjadTSgJeE— LA County Public Works (@LACoPublicWorks) November 20, 2015
The best hypothesis scientists have been able to come up with is that the crumbling, buckling road is the result of a progressive landslide in the surrounding hills. Satellite images going back to 2011 show obvious cracks in the surface of the road, as well as significant shifts in the shape of the hills, perhaps due to getting saturated by a great deal of water at some point.
"[It] appears as though the soil moved underneath the road, and then lifted it up. Which is quite odd," George Dvorsky reports for Gizmodo. "Normally, a landslide would just wipe the road away. Before-and-after pics of the site show that the road is situated on a box cut, and that the unloading of material from the slope likely contributed to the landslide."
The jury's still out on this one, but for now, the 3-km stretch of Vasquez Canyon Road between Lost Creek Road and Vasquez Way is reportedly closed until further notice.
Here's some recent drone footage of the site: