The impressive crater of the Poàs volcano and its steaming lake

The Poàs volcano is located in the province of Alajuela. It lies around 30 km north-west of Costa Rica's capital, San José. The nearest town is Alajuela, around 20 km from the volcano. Volcan Poàs National Park is a fascinating place where nature reigns supreme. It was created in 1971 to protect the active volcano of the same name. Since then, the park has become one of Costa Rica's main tourist attractions, thanks to the dangerous natural beauty of its volcanic landscape.

Volcan Poàs National Park is also an important conservation area for the region's biodiversity. The cloud forests and their canopies are home to a variety of endemic bird species, including the ruby-throated hummingbird, the trogon and the resplendent quetzal. Hiking trails through this incredible biodiversity offer the chance to hear howler monkeys or meet coatis and tapirs.

The Poàs volcano is an active volcano. It rises to an altitude of 2,708 metres, making it the third highest volcano in the country. Poàs is relatively young for a volcano. It began to form around 1.6 million years ago and became a stratovolcano. Over time, its repeated eruptions created a main crater measuring around 1.5 km in diameter and over 300 metres deep. This crater was then filled with rainwater and underground springs, creating an emerald-green lake that gives off sulphurous and acidic fumes.

In recent years, the Poàs volcano has experienced several eruptions, the most recent of which took place in April 2017. During this last one, the main crater ejected ash and rocks very violently, forcing the evacuation of visitors and residents from the area. Since then, the volcano has remained active, with regular gas and ash emissions.

The acid lake

An acid lake is a lake with a pH below 7, which means that it is more acidic than neutral water. Acidic lakes can form naturally, as in the case of the Poàs, but they are often the result of human activity. The Poàs is one of the most acidic lakes in the world, with a pH of between 0.1 and 0.3. It is therefore very important to respect the established safety rules when visiting the national park and its surroundings. The formation of this acid lake is due to the chemical reaction of volcanic gases escaping from the underlying magma and dissolving in the lake's rainwater.

You can visit the Poàs volcano on your own, without a tour guide. The park offers signposted trails that allow you to discover the main crater lake **, the steaming fumes** escaping from the earth cracks, the hot springs and the surrounding cloud forests. However, it is important to note that the main crater is active and presents safety risks. It is therefore important to follow the safety instructions and respect the prohibited areas. Don't worry, everything is explained at the park entrance.

View the crater from the lookout point

The Poàs volcano lookout is located around 500 metres from the entrance to the National Park. The path leading up to it is an easy and pleasant walk, offering breathtaking views of the main crater and the steaming acid lake. It takes around 15-20 minutes of leisurely walking to reach the lookout point from the park entrance.

For a more enriching and informative experience of the volcano, hiring a local tour guide is a good idea. He or she will share with you interesting information about the geology, fauna and flora of the region, as well as the history, traditions and folklore of Costa Rica in relation to the Poàs volcano.