Mexico
At 18,491 feet above sea level, Pico de Orizaba is the third-highest mountain in North America, after Denali in Alaska and Mount Logan in the Yukon.
Mexico is known more for its beaches than its mountains, but the southernmost arm of North America is home to some very big stratovolcanoes (conical domes built up by layers of volcanic deposits), including Pico de Orizaba, the tallest volcano on the continent. Rising from the Trans-Mexican Volcanic Belt, which runs roughly east and west across Mexico, Pico de Orizaba soars to 18,491 feet above sea level. From the air, you can see the lone, snowcapped peak between Mexico City and the Gulf of Mexico; the summit crater stands out amidst the glaciers. Notice there are no glaciers on the volcano’s sunny, south-facing slope: they are long gone.
Pico de Orizaba, also known as Citlaltépetl, is actually made up of three successive volcanoes in the same spot, created in three eruptive stages, each superimposed on top of the other. Volcanism began around 20 million years ago, after the Farallon Plate broke into the smaller Cocos and Rivera Plates, which began subducting under the Middle America Trench off the west coast of Mexico, fueling volcanism several hundred miles inland.
Pico de Orizaba is one of the few places in Mexico that holds snow year-round. On its southwest flank, behind and to the right of the snowcapped summit in this image, stands the 15,225-foot Sierra Negra volcano, now considered extinct.
The most recent eruptive stage began around 16,000 years ago and culminated in the last eruption in 1846, which had a relatively mild magnitude of 2 on the Volcanic Explosivity Index. The largest known eruption occurred in 6710 BC—a magnitude 5 blast that was on par with the 1980 eruption of Mount Saint Helens. Today the volcano is considered dormant, but not extinct, and is carefully monitored for signs of reawakening.
Pico de Orizaba stands out not just for its height, but for its snowy summit—a very rare sight in Mexico. In point of fact, the snow is actually an ice cap made up of nine overlapping glaciers, including Gran Glaciar Norte, the largest glacier in Mexico. These glaciers are fast retreating, as a result of climate change.
Try to catch a glimpse of Pico de Orizaba en route to Mexico City, 120 miles west of the volcano.
