I'm posting just the last part of this article, reading it all from the beginning is recommended, he has done an excellent job explaining current asteroids passing Earth, but it's his conclusion that is a real eye opener, as a dooms day scenario and puts in perspective even the most prepared may not make it, nor would they really want to.

Of course this is the ultimate in worst case scenario, but it may give some insight as to what is truly the most important items to stock up on if things really go bad, not this bad of course, but bad none the less.

WHAT ARE THE IMPLICATIONS OF AN ASTEROID IMPACT WITH EARTH?

All three of these asteroids are registered as "Potentially Hazardous Asteroids" (PHA.) Fortunately Toutatis is the biggest one of these three asteroids which can wipe out life on Earth, and it remains far away. Asteroids earn PHA classification by a combination of Earth-crossing orbit, a certain size and velocity. All these characteristics combine together can enable a PHA to destroy a continent or even the entire Earth. Fortunately, 2012 DA14 and 2012 XE54 are not large enough to cause global or continental damage.

For larger asteroids, water impact simulations show an ocean impact will cause massive tsunamis towering a mile high or even more. Some computer models have shown that two massive tsunamis can be generated upon impact with an ocean and travel outward in opposite directions. These giant waves, which have never been seen in the history of the world can circle the globe. Eventually they will collide with each other on the opposite side of the Earth. There they will reverse direction and returning back to the asteroid point of impact and collide again. It is hard to comprehend short term and long term effects this would have on most of the world's major cities which are located on coastal areas.

A ground impact will be far worse. Scientists have modeled a ground-impacting asteroid. This type of impact will have far more devastating effects on life. Millions of tons of dirt and dust will be blasted into the upper atmosphere. There it will continue to circle the Earth for months, blocking out most of the Sun's light for up to one year. Trees and crops will die after three days if there is insufficient sunlight for photosynthesis.

Cities can be rebuilt and people relocated after a asteroid-created super-tsunami. But losing all of Earth's trees and crops from a strike on land will wipe out both land and ocean ecosystems, destroying all life around the globe. Even oceans can die from a large asteroid impact on land. Plankton is at the base of the ocean food chain and it too, must have sunlight.

In either case, there is the serious issue of shifting the axis of Earth's rotation and altering the wobble. These are entire subjects in themselves and are outside the scope of this article.

Anyone who survives the effects of a large mile wide (or larger) asteroid strike will soon turn feral. A domestic house will turn feral when kept outside for just two weeks. People will resort to robbery, killing and cannibalism in a very short time after all the food is gone. When a plane crashed high in the Andes mountains many years ago, it was cannibalism of those who died which kept remaining passengers alive through the winter. Even though these people knew that eventually they would be rescued when spring came, the pain of starvation and accompanying symptoms was too much for anyone to endure. Now imagine the survival mentality an asteroid strike will create in everyone - seeing civilization as we know it wiped out, no food, electricity, running water, medicine, doctors, hospitals, etc... ever again. Even a simple injury could become infected and life threatening.

When trees and plants have died they cannot be replaced. Even if there were trillions of seeds or seedlings ready to re-plant the Earth, there would not be enough sunlight or oxygen to germinate the new plants and these would also die. Atmospheric CO2 levels for those that survive will rapidly rise without trees to recycle CO2 into oxygen around the world every day. Forget about global warming - all life on Earth will suffocate without oxygen-recycling by trees and plants.

That big seed vault in Norway? It is completely useless without sunlight. It cannot hold enough seeds to repopulate all the trees needed to make Earth livable again. There is also the matter of bees. Without bees to do the pollination of plants and crops, plants cannot produce fruit or vegetables. Did they store billions of bees in the Norway vault? Probably not. It would seem that the Norway vault is just a mental exercise to feel good for some. When things become so bad that the vault must be opened and seeds used - where will the bees come from for plants to grow?

It would take hundreds of years for the world to have trees and bees once again, long after the atmosphere cleared and our Sun shines again. People would have to re-plant all the trees on the planet, starting with seeds. Then use those seeds to make seedlings, etc... But no one would be around to do it because of the lack of oxygen and food, and destruction of civilized life as we know it. Our entire comfortable, civilized world is hanging by a very delicate thread. When technology is broken it may be impossible to repair. Within a few years words like Facebook, internet, emails and texting will vanish from everyone's vocabulary. Survival will be a 24/7 issue for as long as it can go on.

Wasn't all that uplifting? Gives you a new appreciation for the modern life we have today. Hopefully 2012 DA14 will pass by and nothing serious will happen to dozens of complex, hard-to-replace, expensive communication satellites which have become the backbone of our civilization..

The asteroid will pass by at 11:00 am Pacific time, there's a possibility it might take out a satellite or more, they just don't know.
JPL live of the asteroid....
http://www.ustream.tv/nasajpl2

Being a glass half full kind of guy, I'd just be glad to finally have global warming halted. Al Gore would be able to ice skate on his swimming pool.

Which is exactly the point of the thread, good find!
Now had it been a mile across? Point is, no one even knew it was coming, which is why everyone should have some sort of survival plan.
But sadly, 95% of the nation has about 3 days of food and water, beyond that point, law and order will be but a distant memory.

95% of the nation will go into a panic if their smartphone doesn't work for 3 days.

You mean Taco Bell will be closed?

These people can't be reasoned with now; it will be utter insanity if they don't have food and water.

Yep, we are only one catastrophe away from reverting to cavemen.
 
That's the thing, if all Hell breaks lose, no one will be able to go to work because most public utilities will be down.
First there would be a run on foodstuffs and fuel, and most stores don't carry enough for more than a day of panic buying.
Then there is the issue of the impatient ass holes that refuse to wait in line and fights break out, cops won't be able to respond due to the fact they are overwhelmed.
Yes, virtually all societies are ill prepared and run on a fine line of compliance, it only takes one event to upset the balancing act.

I think a lot of us rural people will be okay for awhile. I'm not in full blown survivalist mode, by any means, but I think I could keep us alive indefinitely.......not easily.

I would not want to be in a city.

Same here, granted I never meant to become a survivalist, but living in the wilderness tends to force one to stockpile everything, from fuel and food, to just about everything, like not throwing anything away, you may need the parts for something later. (I know you know what I'm talking about) 
But being snowed in for three weeks a couple of decades back taught me a valuable lesson, always have a huge assortment of dry goods and seasonings on hand.
After awhile, there is only so much you can do with beans and rice when all you have is ginger, pepper and salt in your cabinet.
Of course water is essential, but with several feet of snow outside, that wasn't an issue.

Since those days I have made an effort to always buy two of everything, and now that Toy got into selling freeze dried food, we've managed to build a solid 1 year supply, two if we stretch it, and I plan on taking it out to 5 years as a way of hedging against inflation.

Ya know, it really wasn't all that expensive to stock up, just cut out the junk food, useless entertainment and going out to dinner, and you can easily put away one or two hundred bucks away each month, and in one short year, you have a years supply of food.

Yeah, I need to put away some dry goods. I've got access to water, and a little pond that's close with lots of panfish. The birds and squirrels are almost tame around here, and plentiful. Tons of kudzu vines, which is an invasive species, but the roots are really healthy and can be dried and made into flour. I'm not saying it would be fun, but we would survive.

Interesting, I live to high for kudzu, in fact it's why I have to stock food, there really isn't that much up in the mountains outside of of huge Doug fir or pine trees. Game and water we have aplenty though.

One thing about the south, lots of critters. I'm sure I'd get complaints, but I've got a woodpile full of nice fat grubs. At some point, pretty much anything looks like food. I've actually looked into insects for food. Pound for pound, they are a pretty good deal.

Absolutely! Though the first meal won't go down easy, but if it fills the void, the second will be a welcome sight.
I hope I never ever have to resort to bugs and squirrels .

It's pretty interesting way to kill some time on the internet. Apparently there are bugs that are not only really good for you, but they taste good too. Considered a delicacy in some parts of the world.

Hell, if you look at a crab or a lobster, you wouldn't think about eating them based on looks. Somebody had to be the first.