  In hydrodynamical modelling of ultrarelativistic heavy-ion collisions the
freeze-out is typically assumed to take place on a surface of constant
temperature or energy density. In this work we apply a dynamical freeze-out
criterion, which compares the hydrodynamical expansion rate with the pion
scattering rate, to an event-by-event ideal hydrodynamics at the full RHIC
collision energy. We present hadron spectra and elliptic flow calculated using
(2+1)-dimensional ideal hydrodynamics, and show the differences between
constant temperature and dynamical freeze-out criteria. We find that when the
freeze-out ratio is fixed to one, the different freeze-out criteria lead to
slightly different spectra and v_2(p_T) in the event-by-event calculations.
