The Chelyabinsk meteor was about 60 feet, and (fortunately) it was still high in the atmosphere when it exploded.
Here’s a article about 150 feet of asteroid:
What If Friday’s Flyby Asteroid Hit Earth?
By Stephanie Pappas, Live Science Contributor | February 12, 2013 07:33am ET
“On Friday (Feb. 15), an asteroid half the length of a football field will buzz close by Earth. It won’t hit the planet, but if it did, the collision would create an impact large enough to level 80 million trees — or the entire city of Washington, D.C., and its suburbs.”
see also: https://en.wikipedia.org/wiki/Impact_event#Frequency_and_risk
“Asteroids with a diameter of 7 meters enter the atmosphere about every 5 years with as much kinetic energy as the atomic bomb dropped on Hiroshima (approximately 16 kilotons of TNT), but the air burst is reduced to just 5 kilotons.[7] These ordinarily explode in the upper atmosphere and most or all of the solids are vaporized.[9] However, asteroids with a diameter of 20 m (66 ft), and which strike Earth approximately twice every century, produce more powerful airbursts. The 2013 Chelyabinsk meteor was estimated to be about 20 m in diameter with an airburst of around 500 kilotons, an explosion 30 times the one over Hiroshima. Much larger objects may impact the solid earth and create a crater.”
Thanks, that answers the exact question I was asking about this story.