It was 15-25 kilometers up. An air burst can be worse, but I don’t think it works that high up.
Just FYI, the search for Near Earth Objects (NEO) is conducted world-wide every night by amateur astronomers. The big serious telescopes are not made for such searches because they look long and deep into our Solar System and the Universe. Asteroids close to Earth are too close to be seen.
Its the one major field of astronomy where amateurs contribute very useful information.
The way it works is the astronomer notices that a star has disappeared for a few seconds - meaning something is blocking its light. He reports this (possibly on the NASA NEO site) and other astronomers report the same sighting from their different positions on the globe. Using triangulation etc the size, speed, and path of the asteroid is calculated and entered on a map.