What To Do In A Nuclear Attack: Step-by-Step Survival Guide

Before the Attack: Preparation

Surviving a nuclear detonation starts long before the sirens sound. Your primary goal is to establish a secure location and stockpile essential supplies well in advance. According to FEMA's official nuclear explosion preparedness guidance, preparation is the single most effective action a civilian can take.

• Identify the best fallout shelters near your home, work, and school. Look for thick concrete walls and subterranean levels. Large office buildings, parking garages, and government buildings often offer the best protection.
• Build an emergency supply kit with a minimum of 14 days of food and water. The CDC recommends at least one gallon of water per person per day.
• Purchase a battery-powered or hand-crank NOAA weather radio to receive emergency broadcasts when cellular networks fail.
• Establish a family emergency communication plan that does not rely on cellular networks. Designate an out-of-state contact as a central point of communication.

During the Attack: The First 10 Minutes

The initial blast wave and thermal pulse are your immediate threats. If you are caught outside when the detonation occurs, the following actions are critical. The FEMA Nuclear Detonation Planning Guide (2022) emphasizes that even a few minutes of decisive action can dramatically improve survival outcomes.

• Never look at the fireball. The thermal pulse can cause permanent blindness even at distances of several miles from the detonation point.
• Take cover behind anything that might offer protection from the blast wave — a wall, a vehicle, or a concrete barrier.
• Keep your mouth slightly open to prevent your eardrums from bursting due to the sudden pressure change caused by the blast wave.
• Once the shockwave passes, you have roughly 10 to 15 minutes before radioactive fallout begins to reach the ground. Use this time decisively to get inside a substantial building.

Choosing the Right Building

Not all buildings offer the same level of protection. The CDC's radiation emergency guidance ranks shelter effectiveness by building type. Underground concrete structures offer the highest protection factor, while wood-frame houses offer minimal shielding. When choosing a shelter, prioritize:

• Best: Underground basement of a multi-story concrete or brick building
• Good: Center of a large multi-story office building, away from windows
• Acceptable: Interior room of a brick or concrete single-story building
• Last resort: Interior room of a wood-frame house, away from windows

After the Attack: Surviving the Fallout

Fallout is the radioactive dust and ash that rains down after a nuclear explosion. It is highly lethal in the immediate hours after detonation but decays rapidly. The CDC's radiation emergency resources provide detailed guidance on post-blast decontamination and sheltering procedures.

• Strip off your outer layers of clothing before entering your clean shelter area. Removing clothing can eliminate up to 80% of radioactive contamination, according to the CDC.
• Wash your body with soap and water. Do not use hair conditioner, as it binds radioactive particles to your hair, making them harder to remove.
• Seal all windows, doors, and vents with heavy plastic sheeting and duct tape to prevent radioactive dust from entering your shelter.
• Consume only sealed, packaged food and bottled water. Do not use tap water, as it may be contaminated.
• Monitor emergency broadcasts on your hand-crank radio for official instructions from local authorities.

Radiation Basics: The 7:10 Rule of Radiation Decay

Understanding how radiation decays is your best defense against making a fatal mistake — leaving shelter too early. The most critical concept is the 7:10 Rule of Radiation Decay, which is used by FEMA and emergency planners worldwide.

This is why staying inside your shelter for the first 24 to 48 hours is absolutely mandatory. The rapid decay of fallout radiation means that patience is your most powerful survival tool.

Managing Your Shelter During the First 24 Hours

Once you are inside a shelter, your immediate priorities shift from escape to management. The first 24 hours are the most dangerous period, and how you manage your shelter environment during this time can significantly affect your long-term survival prospects. The goal is to minimize your exposure to radiation while maintaining the physical and psychological wellbeing of everyone in your group.

The most important thing you can do is seal your shelter from outside air. Radioactive fallout particles are carried on dust and air currents. Turn off all ventilation systems, air conditioners, and heating units that draw air from outside. If you have plastic sheeting and duct tape, seal any gaps around windows, doors, and vents. This is not about creating an airtight seal — that would be dangerous — but about reducing the infiltration of radioactive particles. A well-sealed interior room can reduce your radiation exposure by a factor of 10 or more compared to being outdoors.

Water management is critical. Before the attack, if you had any warning, you should have filled every available container with tap water. After the attack, do not use tap water from the municipal supply, as it may be contaminated with fallout particles. Use only your stored water supply. For sanitation, use heavy-duty plastic bags as a toilet and seal them tightly. This is unpleasant but necessary — maintaining sanitary conditions in a confined shelter prevents the spread of disease.

Communication and Information During a Nuclear Emergency

In the aftermath of a nuclear detonation, the information landscape will be chaotic. Cellular networks will almost certainly be overloaded or completely non-functional, both because of the EMP effects of the blast and because millions of people will be attempting to make calls simultaneously. Social media and the internet may be unavailable. Your only reliable source of official information will be emergency broadcast radio.

A battery-powered or hand-crank NOAA Weather Radio is not optional — it is essential. NOAA Weather Radio broadcasts on frequencies between 162.400 MHz and 162.550 MHz and is operated by the National Weather Service. In a nuclear emergency, it will carry official Emergency Alert System (EAS) broadcasts from FEMA and local emergency management authorities. These broadcasts will tell you when it is safe to leave your shelter, where to go for medical assistance, and which areas to avoid.

If you have a working phone with battery power, use it sparingly and only for essential communication. Text messages are more likely to get through than voice calls when networks are congested. Keep a written list of emergency contact numbers — do not rely solely on your phone's contact list, as the phone may be lost, damaged, or its battery may die.

Special Considerations for Specific Situations

The standard shelter-in-place guidance assumes you are at home or near a substantial building when the attack occurs. But life is unpredictable, and you may find yourself in a very different situation. Here is how to adapt the core principles to specific scenarios.

If you are in a vehicle when the detonation occurs, pull over immediately, turn off the engine and ventilation, and duck below the window line to protect yourself from the blast wave and thermal pulse. As soon as the shockwave passes, get out of the vehicle and move into the nearest substantial building. A car provides very little protection from radiation compared to a brick or concrete building. Do not attempt to drive through a fallout zone — you will be exposing yourself to radiation for the entire duration of the drive.

If you are outdoors with no building nearby, look for any depression in the ground — a ditch, a culvert, or even a low spot in the terrain — and lie face down with your hands under your body. Cover as much of your skin as possible. This is a last resort, but even a few inches of earth between you and the fallout provides meaningful shielding. Move to a building as soon as the immediate blast effects have passed.

If you are in a school or workplace, follow the instructions of the designated emergency coordinator. Most large buildings have emergency plans that include shelter-in-place procedures. Move to the designated shelter area, which is typically in the basement or the center of the building on the lowest floor. Account for all people in your group and do not allow anyone to leave to search for family members — the radiation risk outside is too high.

When and How to Evacuate After the Initial Danger Passes

Evacuation should only be considered after the immediate fallout danger has passed — generally after 24 to 48 hours — and only if official authorities have issued evacuation orders or if your shelter is no longer safe. Spontaneous, unplanned evacuation in the first hours after a nuclear event is one of the most dangerous things you can do, and FEMA's guidance explicitly warns against it.

When evacuation does become appropriate, plan your route carefully. Move perpendicular to the wind direction to get out of the fallout plume as quickly as possible. Avoid low-lying areas where fallout particles may have concentrated. Keep your skin covered with long sleeves, pants, gloves, and a mask or cloth over your nose and mouth. Move quickly and do not stop in areas with heavy dust or ash on the ground.

Once you reach a designated evacuation center or clean area, undergo decontamination immediately. Remove all outer clothing, shower with soap and water, and receive medical evaluation if available. Report any symptoms of radiation exposure — particularly nausea, vomiting, or skin redness — to medical personnel immediately.

Frequently Asked Questions

What will happen if there is a nuclear war?

A nuclear war would cause immediate, massive casualties in targeted areas due to the blast, thermal radiation, and initial ionizing radiation. This would be followed by widespread radioactive fallout, global supply chain collapse, failure of the electrical grid (EMP), and severe long-term environmental impacts, potentially including a "nuclear winter" that disrupts global agriculture for years. The IAEA's emergency preparedness resources provide detailed information on the long-term consequences of nuclear events.

What to do if WW3 breaks out?

If World War III begins, immediately execute your emergency survival plan. Relocate away from primary targets — military bases, major cities, and infrastructure hubs — if time permits. Secure your fallout shelter, ensure your stockpile of food, water, and medical supplies is accessible, and monitor emergency broadcast systems via a hand-crank radio. Stay off cellular networks to preserve bandwidth for emergency services.

Which countries have nuclear weapons?

Nine countries are currently known or widely believed to possess nuclear weapons: the United States, Russia, China, France, the United Kingdom, Pakistan, India, Israel, and North Korea. The US and Russia hold the vast majority of the global nuclear arsenal, with each possessing thousands of warheads.

Which countries will survive WW3?

Countries in the Southern Hemisphere — such as New Zealand, Australia, Argentina, and Chile — are statistically more likely to survive the direct impacts of a large-scale nuclear exchange. They are far from primary nuclear targets and are less likely to be severely affected by the immediate atmospheric spread of heavy nuclear fallout, though they would still face severe global economic and climatic consequences.