Lock and lock all windows and doors. Go to the basement or to the center of the building. If possible, turn off fans, air conditioners, and forced air heating units that bring in air from outside. Enter the nearest building to avoid radiation.
With adhesive tape and plastic, cover all windows, doors, faucets, vents, plumbing fixtures, and other forms of outdoor air intake to your shelter. Consider stacking bricks, sandbags, or even household items, such as books, in front of these vulnerable areas. Catarrhal rain is radioactive waste produced by a nuclear explosion that can affect areas far from the explosion site. If you are in a radiation emergency, do your best to get inside as soon as possible.
Preferably seek shelter in the basement of a solid brick or concrete building. Try to stay calm, tune into your local emergency broadcast channel, and follow any instructions given to you by the authorities. Unless you're advised to evacuate, stay still until you're told it's safe to go out. Here's how to act and where to take refuge if you receive an alert about an ICBM or other nuclear threat.
That is, until one of them Googled the safety nuclear bomb how to shelter from the beach and found a Business Insider article titled If a nuclear bomb explodes, this is the most important thing you can do to survive. Although many Americans prefer to ignore the potential threat of nuclear exposure, it is a present danger.