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How large must a meteoroid be to produce a major explosion in Earth’s atmosphere?

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Meteor and meteoroid The Cabin Creek meteorite, an iron (nickel-iron alloy) meteorite that was observed to fall in northwestern Arkansas on March 27, 1886. Its characteristic pattern of “thumbprint” dimples, or regmaglypts, is the result of melting and consequent ablation of its surface as it traveled through the atmosphere. The meteorite is likely a fragment of one of the M class asteroids, which show significant nickel-iron in their surface material.

To produce a major explosion in Earth’s atmosphere, a meteoroid must typically be at least 2 metres (6 feet) across.1

Such explosions, which are often equivalent to at least 1 kiloton of TNT, occur approximately 10 times per year. These events are caused by the catastrophic fragmentation of the meteoroid due to the intense aerodynamic pressure encountered during atmospheric entry, which exceeds the object's crushing strength.1

For comparison, the Tunguska event of 1908 was a significantly more powerful explosion, estimated at 15 megatons of TNT, which flattened trees over a vast area. While smaller meteoroids generally burn up or fragment at high altitudes, those that are tens of metres across can reach lower altitudes before breaking apart, and objects 100 metres or larger may strike the surface with enough kinetic energy to create an impact crater.12