This story that took place in 1942, during the siege of Leningrad, was told by Curzio Malaparte in his book Kaputt. While attempting to escape a wildfire, the horses tried to swim across the Lake Ladoga. But their entrance in the water, which was in the supercooled state¹, caused the sudden freeze of the lake. The astrophysicist Hubert Reeves was the first one to suggest the hypothesis of supercooling to explain this phenomenon.

¹ Supercooling: under certain conditions, and in particular when it contains dissolved gases, water can remain liquid at temperatures below its normal freezing point. Liquid water can then be found at almost −43.6°F (around -40°C), at standard pressure. This state is unstable and the slightest impurity or disturbance may lead to the instant solidification of the water.