Results are highly dependent on the forcing conditions. Impulsive forcings at lower and higher boundary layer wind speeds lead to shear layers at the top of the cold pool that are unstable to Kelvin-Helmholtz (KH) instability, and to KH vortex pairing and wavelength doubling for stronger boundary layer winds and lower initial Richardson numbers. These instabilities drive mixing and expansion of the shear layer until the downstream mean Richardson number approaches Ri ~0.25. For stronger forcing, this shear penetrates well into the crater and leads to substantial scouring of cold pool air. Ramped forcing leads to similar responses at the top of the cold pool, but also to significant excitation of seiches within the cold pool. Oscillatory forcings yield quite different results, notably the lack of significant shear instability at the cold pool top and very strong seiche forcing within the cold pool. The structures of the seiche responses depend on forcing frequency and lead, in most cases, to significant ejection of air from deep in the cold pool into the external boundary layer for relatively weak forcing. Upon cessation of forcing, seiche motions exhibit a spectrum of discrete responses, with the relative distributions of seiche energies reflecting initial forcing frequencies to a significant degree.