Dr. Paul LaViolette has determined that indeed both our species' recent history and that of the crust of our planet, have been both gradual and catastrophic.
Tomorrow is possible.
Or a hundred years from now. Or a thousand. We do seem to be somewhat overdue on an average scale. The volley or volleys with our civilization's name on it would already be well on its way from the Galactic Core. Because superwave-induced changes in the Sun will cause some of the worst damage to the human species unless we avert them by somehow shielding the Solar System.