Scientist said they thought Turrialba was entering a quiet phase, but no one told the volcano.
Just as residents in the vicinity of the mountain were preparing to return to life as usual, the volcano staged a major eruption at 1:19 a.m. today.
The emission was of ash and gases, and some of it reached the metro area. The eruption was estimated to last from 8 to 11 minutes, according to the scientific agencies involved.
The national emergency commission said that ashfall was reported at airport Juan Santamaría and Tobias Bolanos airports. Tobias Bolanos in Pavas suspended operations until 11 a.m. to assess and clean the ash from the runways, while Juan Santamaría authorities in Alajuela did not suspend operations but launched a major evaluation.
The Red Sismológica Nacional said the eruption lasted 11 minutes and that there was considerable activity within the volcano crater with some pyroclastic flows.
Until the eruption today, officials said the volcanic activity was diminishing, The national emergency commission reduced the prohibited zone around the volcano from five to two kilometers Wednesday, and school children in the areas went back to their classes today as planned.
Volcano experts said earlier that they based their prediction that the volcano activity was diminishing from seismic monitoring of the mountain as well as the obvious signs of vapor emanating from the crater instead of eruptive ash.
Still, they characterize the Turrialba volcano as one of the more active in the country that has been erupting and emitting vapor and ash since 2010.
The early morning eruption was caught by cameras that monitor the crater continually.
Ivan Brenes Reyes, president of the emergency commission, reported today that his staffers and other scientists and technicians were at the area to assess the eruption’s effects and conditions of the population, livestock and agriculture.
He urged the population, especially those with respiratory related diseases, to avoid exposure to falling ash. There were many reports of falling ash from localities in the Central Valley.
The Observatorio Vulcanológico y Sismológico de Costa Rica said that these included Coronado, Ipis, San Pedro de Montes de Oca, San Isidro Heredia, San Pablo Heredia, Tibás, Pavas, La Uruca, Sabana Norte, Santa Ana and Alajuela,
The eruption today was the biggest in the last year, and there are many photos of the event and the subsequent ash fall on the social media and the monitoring organizations’ Web sites.