Turrialba Volcano is an active volcano in central Costa Rica that has been explosively eruptive in recent years including 2016 and in January, March and April 2017. Visitors used to be able to hike down into the main crater, but increased volcanic activity in 2014–17, resulting in large clouds of volcanic ash, caused the surrounding Turrialba Volcano National Park to close. However, with the subsiding of the eruptions, the park and volcano reopened on December 4, 2020. The stratovolcano is high and is about 45 minutes from the Atlantic slope town of Turrialba. The summit has three craters, the largest of which has a diameter of . Turrialba is adjacent to Irazú and both are among Costa Rica's largest volcanoes. Turrialba has had at least five large explosive eruptions in last 3500 years. The volcano is monitored by the Deep Earth Carbon Degassing Project. On clear days both the Pacific Ocean and Caribbean Sea can be seen from the summit. Below the summit is a mountain range and montane forest, with ferns, bromeliads, lichens and mosses. Most of the forest is either primary or secondary forest. The volcano is named after its canton, Turrialba, in Costa Rica's Cartago Province. There is no clear consensus on the origin of the name Turrialba, but historians disagree with attempts to attribute the name to the patronym Torrealba (from Aragon in Spain) or from the Latin Turris alba (white tower). The general consensus is that Turrialba derives from the local Indian (Huetar language), but there is no agreement on its actual roots. Activity During the 19th century, the volcano erupted and emitted ash several times (1847, 1853, 1855, 1859, 1866), producing pyroclastic flows. The last major eruption was in 1866. Small signs of activity started in 1996. In January 2001, the volcano reported increased activity, displaying strong fumarole activity at the central craters. The volcanic activities have increased since 2005. On March 31, 2017, the volcano started to show some activity with ash eruptions. The National Park area opened for visitors was closed from 2009 to 2011. On January 8, 2010, a phreatic eruption occurred, creating a new opening near the crater on the southwest, and the temperature increased from . Two villages, La Central and El Retiro, were evacuated. On January, 2012 a new opening on the west of the crater was created after a phreatic eruption. On April 12, 2012, a small