  Reentrant integer quantum Hall (RIQH) states are believed to be correlated
electron solid phases, though their microscopic description remains unclear. As
bias current increases, longitudinal and Hall resistivities measured for these
states exhibit multiple sharp breakdown transitions, a signature unique to RIQH
states. We present spatially-resolved measurements of RIQH breakdown that
indicate these breakdown signatures can be ascribed to a phase boundary between
broken-down and unbroken regions, spreading chirally from source and drain
contacts as a function of bias current and passing voltage probes one by one.
The chiral sense of the spreading is not set by the chirality of the edge state
itself, instead depending on electron- or hole-like character of the RIQH
state.
