Minutes to hours after a nuclear bomb are critical for survival. Disaster experts explain how to protect yourself in a worst-case scenario.

• Putin recently placed Russian nuclear forces on high alert, a concern to some defense experts.
• If a nuclear bomb was headed toward the US, residents would have 30 minutes or less to find shelter.
• Actions immediately following a blast, like showering or staying indoors, could save your life.

President Vladimir Putin placed Russian forces on high alert Sunday, generating concern among defense experts that Russia could trigger a nuclear attack or, in a nightmare scenario, all-out nuclear war. Some military analysts see the move as a strategic response to Western sanctions, while others take it as a warning sign that Putin could resort to nuclear tactics if compelled.

“I’m definitely worried,” Irwin Redlener, a public-health expert at Columbia University who specializes in disaster preparedness, told Insider. “Sometimes we might be tempted to dismiss such a statement, but in the context of what seems like a pretty unhinged Vladimir Putin, who actually carried through on his threats to invade Ukraine with ferocity, we have to take the nuclear comments seriously.”

A nuclear attack remains highly unlikely, but not out of the question, experts say.

Russia’s nuclear arsenal is capable of striking just about anywhere on the planet. If a single weapon was launched at the US, residents would have roughly 30 minutes, or less, to find shelter, assuming they were immediately warned of the attack. If Russia launched a weapon from international waters just outside New York, East Coast cities like New York, Boston, and Washington, DC, might have just 10-15 minutes to prepare.

“You wouldn’t even have time to go get your kids from school,” Redlener said.

The minutes to hours after a nuclear blast is a critical window. The potential for radiation exposure decreases 55% an hour after an explosion, and 80% after 24 hours, according to the Johns Hopkins Center for Health Security.

Immediate actions during those first few hours, like covering your eyes or hunkering down in an indoor shelter, could mitigate your risk of death or serious injury. Here’s how to protect yourself in a worst-case scenario.

First 30 minutes: Avert your eyes and shield your face 

The US doesn’t have a sufficient warning system for nuclear threats, Redlener said.

Hawaii learned this lesson in 2018, when the Hawaii Emergency Management Agency sent out a false push alert to people’s smartphones, warning of an inbound ballistic missile threat. “Seek immediate shelter. This is not a drill,” the warning read. An employee at the agency had sent the alert by mistake.

“It caused chaos,” Redlener said, adding, “Some people just totally ignored it and some people went into panic mode and were jumping down sewer drains with their children.”

Redlener said the best way to learn of an impending nuclear attack is probably TV or radio. Those without immediate access to news reports could hear sirens, he said, but the noise might be confusing. By the time you googled the sirens or called the police department, your time would have run out, he said.

The best course of action is simply to avert your eyes. When a nuclear bomb strikes, it sets off a flash of light and giant orange fireball. A 1-megaton bomb (about 80 times larger than the “Little Boy” atomic bomb dropped on Hiroshima, Japan) could temporarily blind people up to 13 miles away on a clear day, and up to 53 miles away on a clear night. 

The Centers for Disease Control and Prevention also recommends dropping to the ground with your face down and your hands tucked under your body to protect from flying debris or sweltering heat that could burn your skin. If you have a scarf or handkerchief, cover your nose and mouth.

But make sure to keep your mouth open, so your eardrums don’t burst from pressure.

First 45 minutes: Seek shelter indoors, away from windows

A single nuclear weapon could result in tens, if not hundreds of thousands of immediate deaths in a major city like New York or Washington, DC. The number of casualties depends on the size of the weapon, where it’s detonated, and how many people are located upwind of the blast.

Survivors of a nuclear attack have about 15 minutes before sandlike radioactive particles, known as nuclear fallout, reached the ground. Exposure to fallout can result in radiation poisoning, which could damage the body’s cells and prove fatal.

People should ideally look for shelter in the opposite direction of fallen buildings. 

“You’d want to go in the direction away from the wind,” Redlener said, adding, “Get as far away as you can in the next 10 to 15 minutes, and then immediately seek shelter before the radiation cloud descends.”

The best shelters are buildings like schools or offices, with few to no windows and a basement for camping out. If there aren’t sturdy buildings nearby, it’s still better to be indoors than outside.

If you take cover in multistory building, choose a central location and steer clear of the top and bottom floors. If the building has windows, stand in the center of a room. Shock waves can shatter windows up to 10 miles away from an explosion, resulting in flying glass that could injure people nearby.

First 24 hours: Rinse off in the shower and stay inside until further notice

The hours after a blast are critical for reducing radiation exposure.

Doctors can often treat radiation damage with substances such as potassium iodide, though “there are certain dose levels that you can’t do anything about,” Kathryn Higley, a professor of nuclear science at Oregon State University, told Insider. 

But in a disaster scenario, there may not be enough physicians or hospital beds to care for everyone. 

“There are not enough empty burn beds in all of the United States to deal with even a single nuclear attack on one city in the US,” Tara Drozdenko, the director of the Union of Concerned Scientists’ Global Security Program, told Insider.

People who were outside during an explosion should shower as soon as possible, making sure the water is warm and soap is applied gently. Scrubbing too hard could break your skin, which acts as a natural protective barrier. You should also cover any cuts or abrasions while rinsing off. 

Don’t use conditioner, body lotion, or face cream after exposure to a nuclear blast, since these products can bind to radioactive particles and trap them in your skin and hair.

Blow your nose and wipe your ears and eyelids, since debris could get stuck in these orifices. The CDC also recommends sealing outer layers of clothing in a plastic bag, along with any tissues or cloths used to wipe your body or face. 

It’s safe to consume food from sealed containers such packages, bottles, or cans, according to the CDC. You can also eat items from your pantry or refrigerator, as long as you wipe off containers, cookware, counters, and utensils. But anything left uncovered, such as fruits or veggies from a garden, would be unsafe to eat.

Unless you’re told to go outside, it’s best to stay put until the risk of contamination has gone down. The US Department of Health and Human Services recommends staying indoors for at least 24 hours after a nuclear explosion.