  We introduce a local-in-time existence and uniqueness class for solutions to
the 2d Euler equation with unbounded vorticity. Furthermore, we show that
solutions belonging to this class can develop stronger singularities in finite
time, meaning that they experience finite time blow up and exit the
wellposedness class. Such solutions may be continued as weak solutions
(potentially non-uniquely) after the singularity. While the general dynamics of
2d Euler solutions beyond the Yudovich class will certainly not be so tame,
studying such solutions gives a way to study singular phenomena in a more
controlled setting.
