A large glacial lake that formed less than 30 years ago has suddenly disappeared, leaving a snaking, ten-story crater, Chilean park rangers announced this week.

The remote, unnamed lake is in Bernardo O'Higgins National Park, about 1,240 miles (2,000 kilometers) south of the Chilean capital, Santiago. The seldom visited, five-acre (two-hectare) lakebed was brimming as recently as March.

So where did all that water go?

One theory suggests an earthquake opened a crack in the lake floor, draining the lake like so much bath water. Chile-based glacier expert Andres Rivera, though, suggests that ice floes blocking a natural outlet gave way.

It's "not at all unusual," he told the AFP news agency. It just isn't often witnessed.

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