Why was an asteroid with only a 10-15 km (7-8 mile) width able to wipe out the dinosaurs and cause the extinction of 75% of all species on Earth?

Question

That width is less than the distance I drive from my house to the grocery store. Why was that size of an asteroid able to cause such catastrophic damage?

In: 21

Answer 1

Dinosaurs were stressed and losing species millions of years leading to the impact, which caused a huge tidal wave and severe climate change.

Some dinos survived and became Avians, so not totally wiped out.