They were attending a meeting of scientists and adventurers. It took only a few minutes for volcanologist Stephanie Grocke to realize she had found two perfect partners. Grocke wanted to tell the story of a volcanic system she had been studying in Guatemala. Soon, photographer Gabby Salazar and cartographer Ross Donihue were hooked on the idea, too.

In 1902, the Santa María volcano in Guatemala experienced a devastating eruption. It ranked as one of the largest of the 20th century. The event destroyed the surrounding landscape. It left a huge crater in the side of the mountain. It also deposited a lot of ash and volcanic debris. Lava flows began erupting at its base in 1922. Over time, the flowing lava created a lava‑dome complex, named Santiaguito.

Lava domes form when sticky magma erupts from a vent and pours onto Earth’s surface. The magma is then called lava. This lava is too thick and gooey to flow far. So, it piles up and makes a large dome.

Caliente was the first dome. Then the magma moved west to form other domes called La Mitad, El Monje, and El Brujo. Then the magma moved back to Caliente and is now erupting there.

Since 1922, there have been almost continuous eruptions among the four lava domes. They happen so often, they feel routine to those living in nearby Quetzaltenango.

To Grocke, this is the perfect place for studying active volcanoes. And it’s a good place to test a new method to monitor lava‑dome activity.

So, Grocke planned a month‑long expedition with Salazar and Donihue. She wanted to try photogrammetry, a type of time‑lapse photography. It allows you to observe changes over a period of time.

It would help them see changes in the domes. She knew Salazar could help with this. Donihue would map their expedition. He would also make infographics to help show the risks of active volcanoes.