Suddenly, you hear the explosions in the distance while sipping a cold drink from your mountaintop estate. You've heard guns being fired before. You're a Desert Storm veteran, so you've heard bombs as well.
But you've never heard anything like this. After all, as the explosions continue and you look out the window, the mushroom clouds swirl up into the sky like tornados in the distance. Suddenly, you realize that this is the worst case scenario. It's something that your mind only allowed access to in nightmares.
It's a nuclear war.
The good news? The nuclear bombs are being set off a great distance away from you. The bad news?
Nuclear winter is shortly on its way... and you don't have a dog sled.
What is Nuclear Winter?
Nuclear winter is a theoretical concept. In short, many scientists believe that a large scale nuclear war would change the global climate in great proportion. This is because such a war would likely catapult large amounts of soot and smoke (aerosal particles) into the Earth's stratosphere. Along with this, the ash and dust ( which could settle in the stratosphere for months or even years ) would likely travel by wind over a great distance to create a wall between the Earth and sun.
Subsequently, sunlight would have difficulty breaking through, and this would cause the temperatures to drop.
In 1990, a group consisting of R.P. Turco, O.B. Toon, T.P. Ackerman, J.B. Pollack, and Carl Sagan ( called TTAPS based on the last names of the participants ) wrote a paper entitled, "Climate and Smoke: An Appraisal of Nuclear Winter". In this controversial paper, the authors attempted to outline what would happen weather- wise as a result of a nuclear war. Here's what they predicted.
First 1-3 months
Ten to 25% of soot injected would be removed by precipitation. The rest would ride wind and spread across the Earth.
If it were to happen in July ( a July smoke injection ): There would be a 22 degree C drop in mid-latitudes and 10 degree drop in more humid areas. Further, the authors surmised a 75% drop in rainfall, and as much as a 90% drop in visibility in high smoke areas.
Beyond that the authors hypothesized that the ozone could be depleted greatly, leading to a huge increase in dangerous UV radiation seeping through to our world.
Not exactly great news, huh? Good thing is that many scientists have more recently theorized that nuclear winter wouldn't have anywhere near an effect so devastating.
Still, a study gone over at the annual American Geophysical Meeting in December of2006 cited that even a small scale regional nuclear war could mess with the global climate for a decade or more. So, even if the TTAPS crew did overestimate things, the possibility of nuclear winter, especially considering the fact that we're experiencing obvious global climate change without any such happening, is something to worry about. After all, the possibility of these strange climactic events all coming together at once couldn't be a good thing.
Add in the fact that countries like Iran and North Korea are getting into the nuclear game, and the prognosis becomes even bleaker. Oh yeah, and there's also those terrorists wanting to do everyone harm.
Continued below...

Taken together, this would all seem to beg the following question.
Will I Survive Nuclear Winter?
Dealing with UV radiation - First order of business is the fact that ozone depletion could cause an abundance of UV radiation to seep through into our atmosphere. Thus, we would need to deal with this excess radiation, which in high amounts can cause skin cancer and eye problems ( especially to the cornea ). In fact, eye damage can actually occur without any pain or discomfort.
In other words, without warning. Thus, here are some things to consider.
1. Be covered from head to toe when under UV exposure. In other words, protect your skin!
2. Wear a hat and stay in the shade as often as possible ( this is one thing that may be easier than it used to be if a nuclear winter were to occur! ).
3. Use sunscreen with a high UV protection factor.
4. Protect your eyes. Sunglasses can do this, as can lab safety glasses and / or goggles.
5. Remember that children are more susceptible to UV radiation. Protect them without fail.
Dealing with the cold
We really have no idea how cold it could get during a nuclear winter. Some, like the TTAPS crew, have proposed that it's going to get real cold. However, there is a growing feeling in the scientific community that these projections were way too strong. Regardless, with the already changing global climate, it's always better to be safe than sorry. Therefore, here are some considerations in dealing with a longstanding cold spell.
1. Have emergency heating supplies on hand. - Remember that if a nuclear war were to occur, electric, gas, and oil might be off the table. Thus, it might be prudent to have a stove and a surplus of firewood at your home. Further, it couldn't hurt to have excess supplies of your preferred heating fuel stored away safely somewhere.
2. Have appropriate clothing on hand. - Remember that clothing in frigid conditions should keep the body warm, protect the outer extremities, allow perspiration to disperse, allow free movement, and be comfortable. Thus, it is for the most part better to have several layers of clothing on rather than just one very thick layer. This is because the extra layers allow easier movement. Further, perspiration disperses more readily with several layers than with one.
Beyond that, it would seem important to have boots, gloves, and sunglasses / goggles on hand. This may seem obvious to northerners, but remember that a nuclear winter could also reach those in warmer climates not accustomed to such weather.
Have a plan for food
Remember that a longstanding winter would, of course, impact our ability to grow food ( also remember that in a nuclear winter, the amount of sunlight and precipitation would change ). Thus, food would no doubt become an issue even if the rest of our social structure remained intact.
Therefore, finding ways to produce food on your own or within your social network would likely become vitally important. Initially, though, you might want to have a significant amount of non perishable food and water on hand. In fact, no matter what the emergency this could become needed ( tsunami, regular war, a terrorist attack of a different sort, etc. ).
In other words, having a food supply on hand is a necessity in this day and age. Have one ready.
Last, remember that a nuclear winter indicates that a nuclear war has occurred
Seems silly to mention, right? On the other hand, the point cannot be overstated. After all, the consequences of a nuclear conflict will go well beyond global climactic change and a nuclear winter. Depending on the size of the nuclear conflict, there could be widespread social disorder and chaos.
In other words, be ready to protect yourself. How? Check out the following hypothetical article that will point you in the direction of things to consider:
How to Survive the Collapse of Civilization
In sum, no one really knows how a nuclear winter would look. It's a hypothetical set of circumstances. However, scientists all do seem to agree that climactic change would certainly occur because of a nuclear war ( even a small, regional conflict ). Therefore, as with anything, you need to assess whether you believe we're on the doorstep of a possible nuclear conflict. If so, best start getting ready now.
In the end, it's always up to you to decide.