SANTIAGO, Chile -- The Calbuco volcano erupted Wednesday for the first time in more than 42 years, billowing a huge ash cloud over a sparsely populated, mountainous area in southern Chile.

Authorities ordered the evacuation of the 1,500 inhabitants of the nearby town of Ensenada, along with residents of two smaller communities.

The National Mining and Geology Service issued a high alert, barring access to the area around the volcano, which lies near the cities of Puerto Varas and Puerto Montt, a little more than 620 miles south of Chile's capital, Santiago.

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"For us it was a surprise," said Alejandro Verges, regional emergency director of the Los Lagos region where the eruption took place. He said Calbuco wasn't under any special form of observation.

Authorities said a large amount of ash was observed but no hot rocks or lava had been seen by late in the day. No injuries were reported.

The Education Ministry canceled school in communities near the volcano and at least three flights to Puerto Montt were canceled.

The 6,500 foot Calbuco last erupted in 1972 and is considered one of the top three most potentially dangerous among Chile's 90 active volcanos.

Villarica, one of South America's most active volcanos, erupted in southern Chile last month, spewing heavy smoke into the air as lava surged down its slopes and forcing authorities to evacuate thousands of people. The 9,000 foot volcano sits above the small city of Pucon. Tourists flock there for outdoor activities, including hiking around the volcano.

"This is clearly a much larger eruption than the one we saw with the Villarica some weeks ago and therefore we need to take bigger and faster measures," Interior and Security Minister Rodrigo Penailillo said.

He said that the government was sending water in case resources get contaminated by ash and that police and military officers had been deployed to ensure safety and help with evacuations.