The park that includes this volcano covers 2309 hectares, its highest point being 3432 meters (approxim. 10,300 feet) above sea level. There are two theories for the name “Irazu”, one being that it’s a combination of “ara” (point) and “tzu” (thunder), and the other being that it’s named after “Istaru”, a 16th century Indian palisade built in the nearby town of Cot. The park is remarkable because of its surreal lunar landscape. There are two main craters, one is called the “Diego de la Haya” crater that contains a strangely colored lake (some days it’s light green and others it’s red) and the other is 300 meters (900 feet) deep. Even the scarce and austere vegetation contributes to the other-worldly feeling of the place. Nevertheless, there are some species of animals that manage to live in this severe and rugged area - coyotes, tiger cats, long-tailed weasels and some species of birds like the clay-colored robins.
Another factor that contributes to the uniqueness and bizarre quality of the place, is the temperature. The average temperature is only 7.3 c or 45 F, but frosts aren’t uncommon, especially at night. It’s more pleasant to visit the park during the driest months of March or April, since the cold weather is enough to deal with. Luckily, there is a snack wagon near the entrance that provides hot coffee and chocolate as well as food. There are also bathroom facilities and picnic tables near the parking lot.
Imagine having to sweep the sidewalk and cleaning the gutters and roofs of your home everyday, because of tons of ash that fall from the sky. Imagine walking around with an umbrella in order to avoid getting dirty, or driving with the headlights on even in the daytime. These are not scenes from a weird Hitchcock movie, they are real situations that occurred when the Irazu volcano erupted on March 19, 1963. The volcano had the nerve to erupt on the same day that President John F. Kennedy visited Costa Rica. For the next two years after the eruption, the volcano spewed showers of ash that went as far as San Jose, and that damaged many crops and homes. The volcano’s first recorded eruption had occurred in 1723, during colonial times, but the 1963 eruption seems to have been much worse.
One of the craters measures 1.5 kilometers in diameter (0.9 miles) and is 300 meters deep (900 feet). At the bottom of this prehistoric-looking hole, there is a medium sized lagoon, that spews boiling sulphurous gases. The other crater is the one mentioned above, called Botos Lagoon, which unlike the other lake, contains cold water that connects to the Rio Angel, and later to the large Rio Sarapiqui. The volcano has had a long history of eruptions, going back as much as 11 million years ! On January 25, 1910, the volcano spewed out 640,000 tons of ash, and in the period of 1952-1954, it bombarded nearby areas with ash and rocks. Since then, the Poas has maintained a low profile, but as recently as 1989, the park was closed because of dangerous sulphurous gas emissions. Its geyser-like eruptions of muddy water and steam, have given it the reputation as the world’s largest geyser.
Apart from its volcanic activity, this national park offers four different habitats; this, in a relatively small area, is evidence of Costa Rica’s incredible biodiversity. The four habitats are the following: areas with scarce vegetation, a stunted forest, a cloud forest, and an area of arrayans. There are 79 species of birds in this park, including the robin, the hummingbird and the spectacular quetzal. Among the mammals found here, are the coyotes, long-tailed weasels, skunks and some small felines. If you see a green-yellow squirrel, take a good look at it, because it’s the Poas green-yellow squirrel, and as its name suggests, it’s only found in this park, and nowhere else in the whole world! One of the most interesting ecosystems present at the park, is the dwarf or stunted forest, where the tough ferns and bonsai-type trees aren’t allowed to grow much because of the acid rain that’s emanated from the volcano.