The scenario is the following: a civilization with technology level similar to humanity's current, on a planet similar to Earth, shall be hit by a massive celestial body in approximately one year.
The impact would be around three times more powerful than the one that caused the end of dinosaurs, but still not enough to completely destroy the planet.
The civilization know about it one year before impact, and know precisely when and where it would crash.
My question is: what would be the best way to save as most people as possible ?
Is there a way to destroy the asteroid ? or at least to damage it and reduce the impact strength ?
Else, what kind of preparations could be efficient, for the impact itself as well as adaptation to what the planet and its life forms would become after it ?
Is there a chance of long-term survival at all ?
I wonder as much for the explosion (or waves, depending if the asteroid crash on land or on ocean) as for consequences for potential survivors: animal and vegetable kingdom would be shaken, so if a large group survives, could a civilization rebuild just after?