The Tunguska event was a large explosion that occurred near the Stony Tunguska River, in Yeniseysk Governorate, Russia, on the morning of 30 June 1908. The explosion over the sparsely populated Eastern Siberian Taiga flattened 2,000 km2 of forest yet caused no known human casualties. The explosion is generally attributed to the air burst of a meteoroid. It is classified as an impact event, even though no impact crater has been found; the object is thought to have disintegrated at an altitude of 5 to 10 kilometres rather than hit the surface of the Earth.
100 years later a similar event happened near a the northern Alberta city of Grande Prairie. On October the second 2008, a meteor crashed leaving a water-filled hole and spewing gases across the city. Many residents became ill, apparently from the noxious gases, shortly after the impact. The meteor had been tracked for 20 hours as it approached Earth and as it fell through the atmosphere and impacted.
Residents reported seeing a fireball and explosion above the city. The object’s air burst occurred at an altitude between 30 and 50 km above the ground and about 1,500 people were injured, mainly by broken window glass shattered by the shock wave.
