A 12-year-old girl died while tunneling through a snowbank outside of her Illinois church on Sunday.

Authorities were called to Rothem Church in the Chicago suburb of Arlington Heights on Sunday afternoon after the girl and her 9-year-old friend were found trapped in the snow.

The girls had dug a tunnel through a large snow bank created by plows, Chicago's WGN reports. Arlington Heights police said the makeshift fort collapsed on the girls while their families were attending a church service. The girls' families found them under the snow about an hour later. It was unknown how long the girls were trapped.

It was about 14 degrees at the time.

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The 12-year-old girl was pronounced dead less than two hours later, Chicago's Daily Herald reported. Her father said he is the pastor of the church where she was playing, ABC 7 Chicago reported. She was the youngest of three children and is remembered as a smart sixth-grader with dreams of being a veterinarian.

The 9-year-old was treated for hypothermia at a local hospital and is expected to survive, according to the Chicago Sun Times.

Police said in a statement that this was a "tragic accident."

Contributing: The Associated Press

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