  We explore the interaction between Hall waves and mechanical failures inside
a magnetar crust, using detailed one-dimentional models that consider
temperature-sensitive plastic flow, heat transport and cooling by neutrino
emission, as well as the coupling of the crustal motion to the magnetosphere.
We find that the dynamics is enriched and accelerated by the fast,
short-wavelength Hall waves that are emitted by each failure. The waves
propagate and cause failures elsewhere, triggering avalanches. We argue that
these avalanches are the likely sources of outbursts in transient magnetars.
