1 Introduction Excess ice—ground ice exceeding the pore volume that the ground would have under natural unfrozen conditions [1]—is a key concept in permafrost science, with relevance across geomorphology, geotechnical engineering, and climate research. The term “excessive ice” and “excess ice” appeared in early foundational works of Taber [2], Pihlainen and Johnston [3], and Mackay [4, 5], reflecting the early recognition of its importance in frozen ground environments.
