The top string of temperature sensors on the moorings was
attached with weak link so that it would detach if caught on an
iceberg and prevent the whole mooring from being dragged away.
Having lost its buoyancy, the entire mooring fell to the
seafloor. The moorings were designed to be pushed down by
iceberg keels and float back up upright after the icebergs
passed. Scientists knew the moorings they deployed in Sermilik
Fjord would be in harm's way of icebergs. But a huge iceberg
pushed one of the moorings down to a depth where the water
pressure was so high that the mooring’s top float imploded.