Most of the forests and vegetation burned, filling the entire atmosphere with soot, smoke, and toxic gases. Acid nitrogen oxides from the atmosphere reacting with itself in the enormous heat and from burning vegetation, and sulfur oxides from the meteor and from the instant impact vaporization of 80,000 cu. Almost all other creatures starve and or freeze. An even worse extinction happened 225 million years ago. Such a monster smiting the Earth at 28 mps would heat the atmosphere to sterilizing temperatures, boiling off the oceans and roasting us into oblivion.
Faster ones crush to dust or explode in the incredible deceleration of the atmosphere.
Although they supposedly never hit Earth, meteor showers are among the most impressive events to see. In 1966, the Nov 16-17 Leonid meteor shower provided the greatest show on Earth. Apparently somebody was glad I arrived.