A relatively large meteorite (40 meters in diameter) hit the earth in what is now Arizona about 50,000 years ago during the late Pleistocene era. It is estimated that the meteorite had the density of iron (7870 kg/m3), weighed about 300,000 tons, and was traveling with a velocity of 12 to 20 km/s (27,000 to 45,000 mph).
- Diameter: 502.3 m
- Density: 3000kg/m3 (dense rock)
- Angle of impact: 60 deg
- Velocity: 17 km/s (38,000 mph)
- Target: Sedimentary Rock
- Distance: 65 km (40 miles)
|S. Nelson, Tulane U., 11/16/11|
People in this zone will suffer third degree burns over much of their body. The ejecta from the impact will arrive in less than 2 minutes, the blast wave in 3.25 minutes. Wind velocity will reach 237 mph. The sound intensity will be 95 dB. Multistory wall-bearing buildings will collapse. Wood frame buildings will be destroyed. Glass windows will shatter. Up to 90% of trees will be burned and/or blown down and the remainder will be stripped of leaves and branches. In Seattle and Portland, some 400 miles away, the impact will feel like a 7.2 magnitude earthquake. A fine dusting of particles and some larger fragments will fall on the cities.
The impact would put large quantities of dust into the atmosphere, blocking incoming solar radiation. Wildfires would be widespread, putting more dust, as well as smoke into the air. The dust could take months to settle back to the surface. Meanwhile, the region would be overcast and dark, and temperatures would drop. This would result in a drop in temperatures.
Blockage of solar radiation would also diminish the ability of plants to photosynthesize, seriously disrupting agriculture, which might take years to recover. If the asteroid impacted in the Columbia River, the consequences would be even more catastrophic (for the purposes of this essay, I am not addressing the remote possibility of the asteroid impacting in the Hanford Nuclear Reservation, the consequences of which would be dire, but essentially unknowable).