A volcano in Chile that had been inactive for over 50 years suddenly erupted twice in the space of hours, blasting huge clouds of ash into the air and forcing the evacuation of around 5,000 people. There were no immediate reports of injuries after the eruptions from the Calbuco volcano in southern Chile late Wednesday and again before sunrise on Thursday. However, one person - a 21-year old mountain climber who was in the vicinity at around the time of the eruption - has been reported missing. A state of emergency was declared after the first eruption, and air traffic was disrupted. Chilean TV aired spectacular footage of ash, bright orange flames and flaming rocks belching from the mouth of the volcano. As far away as southern Argentina, a fine layer of ash settled on roadways and buildings, and officials urged residents to stay indoors as a health precaution. The first eruption, lasting nearly 90 minutes, spewed a giant mushroom of ash 10 kilometers (six miles) into the sky. Chile has about 90 active volcanoes, of which Calbuco is the second to erupt since early March. Officials ordered an evacuation for a 21-kilometer radius around the volcano and the interior ministry rushed in the army to temporarily take control of the province of Llanquihue and the town of Puerto Octay. The National Geology and Mining Service said the volcano might start oozing lava, raising the possibility of mountain-top snow and ice melting, causing floods and raising water levels in rivers.