The landscape of Irazu Volcano National Park is the only place in the Central Volcanic Range system that has rainforest and sub-alpine paramo – wind-swept, treeless plains situated from 10,827 to 13,124 feet.
The area around the volcanic craters resembles a moonscape, a vast expanse coated with black ash. One of Costa Rica’s active volcanoes, Irazu infamously erupted in 1963, raining clouds of ash on Cartago, San Jose and most of the Central Valley for nearly three years.
Volcanologists speculate that Irazu Volcano has been erupting for over 500 years. It has recently entered a dormant phase to the great relief of farmers and property owners along the slopes.
On a perfectly clear day, visitors can see both the Caribbean and Pacific coasts from atop the volcano. The principal crater, some 3445 feet in diameter, is filled with lime green water. Depending on mineral concentrations, the lagoon can also take on a red hue.
The craters here are fringed with a battered collection of bushes and trees, the remains of forests and grasslands damaged by eruptions and vapors. Wind-twisted oak and cedar trees, interspersed with poor man’s umbrella plants and patches of scrubby grass add to the area’s otherworldly feel.
Temperatures hover around 45-55 ºF, and strong winds are common, so bring a sweater. The best time to view the craters is early in the morning, as cloud cover usually thickens after 10 a.m. Visitors during the dry season (December- April) are more likely to get clear views.