Vapor put out by the Volcán Rincón de la Vieja probably is normal and there are not other signs of eruption, said the Observatorio Vulcanológico y Sismológico at Universidad Nacional.
Experts from the national emergency commission flew over the volcano Tuesday and said that heavy clouds kept them from seeking the crater. However, they said they failed to detect any indications of slides on the sides of the crater. In addition, neighbors of the mountain have not heard any loud noises that suggest an eruption, the Observatorio said.
The volcano and a national park by the same name are in north central Costa Rica. The mountain has been active with some eruptions throwing material out of the crater into a nearby river. The volcano was reported waking from a long slumber in September 2011. Since then it has been under observation.
The report early Tuesday of vapor came from local police.