After weeks of waiting, many cautiously returned to their abandoned homes and lives. But the fear didn’t end with that eruption in August. Cotopaxi continued to spit ash and to rumble with dozens of small explosions. It was obvious the volcano was merely warming up. When would it finally blow—and would those in its path have time to escape?

“We were having the signs of acute stress,” Ana Jácome said. “Nobody was sleeping, everyone was freaking out.” Her mother eventually went on antidepressants; Jácome, who was pregnant, moved 20 miles away to Quito for the duration of her pregnancy.

Although experts don’t know when Cotopaxi will erupt again, they believe it will—and that the next time will be much worse. But what those experts can’t say is when the disaster will happen. It could be a month from now; it could be in a decade, or even longer.

“Of the five eruptive periods from 1532 to now—and this is number six—it always ends (or at least has) in a major eruption,” said Patricia Mothes, a volcanologist with the Instituto Geofísico.

What Mothes calls a “major eruption” would produce more than 100 million cubic meters of ash—a column at least 12 miles high. In such an event, more than 200,000 people in Cotopaxi’s shadow alone would be directly or moderately affected. Roads would flood, clean water would become scarce, electricity wouldn’t work, homes and cars would suffer damage. Thirty miles away, Quito would be coated in ash, and air traffic for hundreds of miles would grind to a halt.

Each town on Cotopaxi’s slopes received a map of the risk zones, shaded red, pink, and orange. Those in the red zone, closest to the volcano’s mouth, would need to flee in the event of a major eruption—but some would inevitably be stranded. Not everyone living on Cotopaxi’s slopes has access to a vehicle or, for that matter, another place to stay.

“There are a lot of people just kinda left out,” Mothes said of this scenario. “They have to hunker down under a wood table.”

But even while Cotopaxi bides its time for its big finale, residents have already had their lives disrupted by the smaller explosions.

“All of the communities have already had ash fall,” Mothes said. “Their livestock [have been] affected by the ash fall.”

As residents around Cotopaxi uneasily returned to their daily lives, the cloud of potential catastrophe hung over them. The danger shifted to a quieter and more insidious threat: mental health. Those within Cotopaxi’s risk zone soon began showing signs of depression, anxiety, and even PTSD—sleeplessness, bouts of crying, and episodes of bad temper, said Sandy Ordonez, a psychologist working in a school near the red zone.

“We feel fear because we do not know what will happen and how we can take care of ourselves and our students,” she wrote in Spanish.

“It was a huge traumatic event for many people,” said Theofilos Toulkeridis, a member of the Research Group of Internal and External Geodynamics at Quito’s Universidad de las Fuerzas Armadas ESPE. “The people are still traumatized.”