how does a lake disappear?

apparently, an entire lake has disappeared in Chile, and not a small one. according to the article i read, they think it happened overnight, which sounds a little improbable to me, but then again i'm not an expert on lake disappearances. the scientists were doing some stuff around the Tempanos Fjord when they made the gruesome discovery. plus, as it was the source of a river that was providing water further down the valley, it's a bit of a problem...