He saw that an underground spring flowed under the ice at that spot.

VOA: special.2010.05.01

When spring comes, dry ice warms up and expands.

BBC: Doubts over water on Mars

It is thought the search for the meteorite will be delayed until the ice melts in the spring.

BBC: Russia sends clean-up team to meteorite-hit Urals

This triggered an early spring melt, which made the ice vulnerable to the impact of high summer temperatures.

BBC: Record ice loss in Arctic