When Soil Swells Upwards During Freezing Weather

This page is the CodyCross answer for the clue below from Past and Present Tech, Group 1458, Puzzle 1 (Overhead Projector).

Question is: When Soil Swells Upwards During Freezing Weather

and the answer is: HEAVING

Word Meaning:

HEAVING — present participle and gerund of heave

Definitions from Wiktionary.