  We study the diffusion annihilation process which occurs when spin ice is
quenched from a high temperature paramagnetic phase deep into the spin ice
regime, where the excitations -- magnetic monopoles -- are sparse. We find that
due to the Coulomb interaction between the monopoles, a dynamical arrest
occurs, in which `non-universal' lattice-scale constraints impede the complete
decay of charge fluctuations. This phenomenon is outside the reach of universal
mean-field theory for a two-component Coulomb liquid. We identify the relevant
timescales for the dynamical arrest and propose an experiment for detecting
monopoles and their dynamics in spin ice based on this non-equilibrium
phenomenon.
