  I study the dynamics of a superfluid vortex in a random potential, as in the
inner crust of a neutron star. Below a critical flow velocity of the ambient
superfluid, a vortex is effectively immobilized by lattice forces even in the
limit of zero dissipation. Low-velocity, translatory motion is not dynamically
possible, a result with important implications for understanding neutron star
precession and the dynamical properties of superfluid nuclear matter.
