The Calbuco volcano in southern Chile erupted Wednesday afternoon, spewing heavy ash high into the sky and forcing the evacuation of thousands of people who live in the area.

President Michelle Bachelet will be traveling to the affected area on Thursday.

Calbuco, located near the cities of Puerto Varas and Puerto Montt, erupted into a huge ash cloud. Although the area is mountainous and not as populated as farther north in the country, the government issued a red alert and ordered the evacuation of everyone within a 13-mile (20 km) radius, reports Reuters. More than 4,000 people have been evacuated so far.

Most of the focus has gone into evacuating people from the town of Ensenada and the surrounding municipalities. No injuries or casualties have been reported so far, however one hiker remains missing.

Flights to and from Puerto Montt as well as the Argentine city of Bariloche, across the border, have been cancelled. According to the Associated Press, schools in the affected area have been closed. Calbuco is some 620 miles south of the capital Santiago.

Although Calbuco is one of Chile’s 90 active volcanoes, the volcano was not under observation, Alejandro Verges, regional emergency director of the Los Lagos region told the AP. “For us it was a surprise,” he said.

“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, referring to the eruption of another volcano last month. That eruption also prompted mass evacuations.

On Twitter, the Chilean government said President Bachelet would travel to the affected area “to be with the affected families.”

Before leaving for southern Chile, President Bachelet said there could be lava flows as well as the melting of snow, which could possibly lead to landslides, according to La Tercera. She cited information by the National Geology and Mining Service (Sernageomin), which detected telluric shifts. The agency also estimated the ash coat could be between half a meter to a meter thick.

“There is no supply problem, with drinking water or basic services. The main problem concerns breathing issues because of the ash,” President Bachelet said.

The Twitter account of the Carabineros de Chile, Chile’s national police, said hundreds of officers have been transported to the affected area to help.

The police force has even been helping evacuate pets out of the affected area, as shown in photos on Twitter.

Watch what happened following the first eruption from the town of Mirasol. 

Watch as Carabineros assess volcanic activity from the air.