Temporal degrees of freedom open new capabilities to control electromagnetic interactions with structured media. While rapid changes in effective material susceptibilities, comparable to the carrier oscillation period, suggest emerging new peculiar phenomena, experimental realizations lag theoretical predictions. However, effects inspired by slow, practically realizable parametric changes in effective media possess both fundamental interest and immediate practical applications. Here we perform comprehensive studies of modal hierarchy in a deformable Fabry-Perot resonator, constructed from a wire array, embedded in a compressible dielectric host. The lattice parameter of the wire media can be adjusted within a 3-fold range (from 10 to 30 mm), resulting in extraordinary electromagnetic tunability. Furthermore, the resonator response demonstrates an extreme sensitivity to mechanical deformation as resonance hierarchy in metamaterial assembly strongly depends on the lattice constant. Specifically, a 0.3 mm change in the lattice constant, being as small as ∼0.002λ, shifts the Fabry-Perot resonance frequency range by 1.7–1.8 GHz. Due to their exceptional responsiveness, deformable electromagnetic metamaterials can function as adaptive components, enabling new types of wireless communications where the frequency, bandwidth, and signal direction can be dynamically adjusted in real-time to accommodate varying environmental conditions and user demands.