Not really that strange. That area is known for above average seismic activity. Obviously an earthquake opened a crack beneath the lake and it drained away, leaving the icebergs. Plus, the article states that the lake wasn't even there 30 years ago. Just a case of easy come, easy go.
Perp Reviewed by Perp on . Lake vanishes overnight in Chile This is strange. BBC NEWS | World | Americas | Lake disappears suddenly in Chile Rating: 5