A fast-moving wildfire in Colorado is advancing towards the ADX Supermax, the maximum-security federal prison known as the "Alcatraz of the Rockies" that holds some of the world's most dangerous inmates, including cartel boss Joaquín "El Chapo" Guzmán, convicted terrorists and notorious murderers. The facility was designed to resist riots, hunger strikes and escape attempts, but a wildfire represents a threat it was never built to withstand, prompting officials at the federal Bureau of Prisons to go on high alert as they scramble to protect the site.

Fire crews have been bulldozing firelines around the 37-acre complex, and inmates have been ordered to "shelter in place" rather than evacuate — a measure that is without precedent in the prison's history. Sources familiar with the facility said they would be surprised if an evacuation were ordered, with former inmate Jack Powers, who spent 14 years in solitary confinement there, remarking that "hell would have to freeze over" before prisoners were let out. Experts reportedly say they are less worried about flames reaching the largely concrete-and-steel structure than about heavy smoke entering the building and affecting those held inside.