Summary
A 27-inch asteroid, C0WEPC5, entered Earth’s atmosphere over Siberia on Tuesday, creating a harmless but visible fireball.
This marked Earth’s fourth detected asteroid strike of the year and only the 11th “imminent impactor” ever recorded.
The asteroid was detected by the Kitt Peak National Observatory ahead of impact, showcasing advancements in asteroid detection.
Separately, a larger asteroid, 2020 XR, measuring 1,200 feet in diameter, will safely pass Earth on Wednesday at a distance of 1.37 million miles.
350m is definetely going to make a strong impact.
The Tunguska Asteroid was expected to be 50-60m in width https://en.wikipedia.org/wiki/Tunguska_event
And that released 3 - 50 Megatons of energy. For reference the nukes on Hiroshima and Nagasaki had about 20 kilotons. So about a one thousands of that. The greatest man made explosion, the sowjet Tsar bomb had about 50 Megatons of energy.
A 350m asteroid has about 7 times that length and probably at least three times the diameter. So we are looking at an impact with the mass of at least 50x that, so 150 - 2500 Megatons. If that hits central Europe the immediate blast would probably kill a few hundred million people.