A 150 foot wide asteroid speeding along at 6.15 km/sec (or 2237 mph) will make a very close approach to Earth on Friday February 15, 2013. This asteroid, named 2012DA14 will come within 17,200 miles of the Earth’s surface. This distance is well under the distance to the Earth and Moon, and is so close, in fact, that it will be within the orbiting distance of many satellites. And like so many end of the world novels have started, NASA has assured mankind that the asteroid will NOT hit the Earth on February 15, and only has a 1 in 500 chance of hitting Earth in either its next passes in 2080 or 2109.
The rest of this article is speculation, and not meant to imply this will hit us. It is to look at the event from a personal and family emergency preparedness standpoint.
With the mass and speed of its travel, an asteroid like 2012 DA14 would hit the Earth with the energy of a 3.5 megaton bomb (a megaton is a measure of the explosive force of one million tons of dynamite). This assumes the asteroid will not break up in the Earth’s atmosphere. In truth, our atmosphere is a great shield for fast moving and low mass space objects. As the friction of entry causes most things to burn up, break apart, and rarely even hit the ground. Bad sci-fi movies have told us an asteroid breaking up in the atmosphere would just widen the destruction due to multiple impacts, but in truth, an asteroid breaking up makes for smaller pieces, all with a better chance of incinerating themselves before landing, and making a far smaller impact if they do.
With this type of explosion, concrete structures up to about 3 miles away could be flattened, and the effects could be felt for between 20 and 150 miles depending on the nature if the strike. A similar strike was suspected in the Tunguska Event, but that strike was likely at least 5 times stronger. The nature of the aftermath would depend on the location of the strike. If in an urban center it would be far more devastating, obviously, as typical urban conditions apply. These would include utilities such as gas, electricity, and water causing their associated malfunctions, but would include the damage/destruction of chemical storage and manufacturing, and the expulsion of multiple chemicals and substances used in industry. The weather patterns would direct where this potentially poisonous cloud of aftermath went, and could cause more harm and long term health conditions further away.
Atmospheric effects would be somewhat minimal. There would be a lot of debris kicked into the air, similar to a volcano explosion and tons of debris being carried away. This would not be a “planet killer” event that would block the sun for months, and would have minimal long term effect on the Earth. It would likely temporarily disrupt air travel and airborne rescue operations in the area of the impact.
Fortunately, humans actually occupy very little of the Earth’s surface, and even less in great population density. An asteroid hit is likely to hit water, then low population density areas, before it hits a major area. This is simply due to the Earth’s water to land ratio and population centers.
So, how does one prepare for this? Realistically in the same manner as a hurricane, tornado, and possibly a flood (if you live near large bodies of water). Having a basement with a shelter area is always a great idea if possible to avoid the initial shockwave. Securing one’s homes and possessions in a safe way to try to preserve them, and having enough food and water on hand to sustain your family until help can arrive or you have be evacuated will help cope with the aftermath. Know where the water and gas shut off valves are for your home and know how to work them.
For evacuation, it may be unlikely that roads will be open and available due to debris and downed trees and poles, so one is likely going to rely on a concerted evacuation effort. This is strong reinforcement to have supplies on hand so waiting for a rescue is not introducing new dangers.
The randomness of when/where an impact will occur is the biggest variable, and unfortunately not something people can have an effect on. Staying aware of the news, making pre-planning a priority, and sheltering as needed is what can be done for most. The size and composition of the asteroid will determine the severity, which is also out of our control.
Plan for what you can, but plan to live.