A fire official says an air pocket saved the life of a 6-year-old boy who was trapped for more than three hours under 11 feet of sand at an Indiana park.

Michigan City, Ind., Fire Chief Ronnie Martin told WSBT-TV on Saturday that firefighters felt the air pocket while poking around for the boy Friday at Indiana Dunes National Lakeshore park along Lake Michigan.

He says firefighters then prodded something soft, saw the boy's head and pulled him out.

Authorities say the boy was playing on a dune that was cordoned off for restoration when he fell partially into it. It completely collapsed in on him while his family was trying to pull him out.

The boy was flown to a Chicago hospital for treatment. His condition hasn't been disclosed.