It's happened:
a nuclear explosion.
If you weren't killed in the initial blast,
the fallout can finish the job.
Whether it's an act of war
or terrorism,
all that really matters
in the moments after the blast
is that there are ways
to save yourself and your loved ones.
The worst thing about a nuclear attack
is that there are multiple ways it can kill you.
The explosion, the heat, and the radiation
can all cause damage and death.
In this day and age,
a nuclear device can be small enough
to be concealed and carried
by a single person,
or it can be a missile.
You could have a few minutes' warning
or no warning at all.
The flash from the bomb can kill you
by burning or vaporizing you.
After that, a shockwave can crush your house
or smash you with debris.
If you survive the initial blast,
your first problem is radiation fallout.
Fallout is radioactive soil and debris
that rains down on us after the blast.
Why is radiation fallout dangerous?
It damages the very cells
that our body is made of.
Radiation is energy
moving as waves or particles,
and it exists everywhere around us,
including in the Sun, soil and rocks.
That kind of radiation
is considered to be low-level radiation
and it's fairly safe.
Medium-level radiation causes
fever, headaches and vomiting.
High levels of radiation
damage your internal organs severely
and can kill you.
A nuclear attack is definitely
in the high-level category.
So, what is your first priority after the blast?
Well, the radiation fallout
takes about 15 minutes
to come down to ground level
after the explosion,
so in that time, you need to take cover.
Brick or concrete buildings
will protect you best against radiation. 
However, you don't have much time,
so don't waste it by looking around.
It's important to get inside any structure,
as soon as you can.
Take off your clothes – they're contaminated.
Stay away from the roof
and the outer walls of the building.
Go to the basement
or the middle of the building.
The most dangerous fallout
is during the first few hours
after the explosion
because the radiation is most powerful then.
Keep your loved ones inside,
including your pets.
If your family is separated,
don't try to get together for the first 24 hours.
It's most important for everyone to stay inside,
wherever they are.
If your cell phone, TV, and internet
are all unavailable because of the attack,
try battery operated or crank radios.
Tune into any media you can
to find out when it is safe to exit,
and where you should go to stay safe
and to reunite with family.
The worst thing you can do
is to get in your car and get stuck in gridlock
along with everyone else
as the fallout comes down.
As always, it's best to prepare ahead of time
for dangerous events.
You're probably not expecting
a nuclear attack,
but it doesn't hurt to be prepared.
Look around to identify potential shelters
near your school, work or home.
Prepare an emergency supply kit
and keep it in potential shelter locations.
This kit should include bottled water,
packaged food,
medicine,
and a flashlight.
And, buy a battery powered
or crank radio, as well.
A nuclear attack is devastating.
And depending on its size and how close
you and your loved ones are to the explosion,
it could be deadly.
It could also lead to ruined cities,
dysfunctional societies,
and sickness.
However, if you're prepared ahead of time
and you follow this advice,
you'll improve your chances
of surviving a nuclear attack.
But if you're looking something
to pass the time while waiting for Doomsday,
you can always learn how to survive
other life-threatening encounters.
Do you know what to do
if you're attacked by a gorilla?
Well, you can learn,
next time on HOW TO SURVIVE.
