Where did you get this from? The book recommends 14 days underground if you are in an area hit by fallout. After this, radioactive fallout will have decayed to levels that are not immediately lethal. If you have a reliable dose rate meter that can detect high dose rates, use that to judge if your area is safe.
Underground shelter should ideally have one meter of soil between occupants and all surface area that could contain fallout. Air should ideally be filtered, water should definitely be.
You have around 30 minutes after the blast before fallout hits the ground. Rain accelerates this. You can use the prevailing wind direction to judge whether you are downwind of a detonation. Ground detonations produce fallout, air detonations hardly do.
Lethal effects from a detonation is the initial, instantaneous flash, then pressure wave and explosive debris/structural failure that accompanies it, then radiation from fallout and radiation from ingested radioactive material.
This is a quick recap after reading this book some years ago.
"Try to maintain a distance of at least six feet between yourself and people who are not part of your household. If possible, wear a mask if you’re sheltering with people who are not a part of your household. Children under two years old, people who have trouble breathing, and those who are unable to remove masks on their own should not wear them."
Contracting COVID is the last thing you want during WW3.
Underground shelter should ideally have one meter of soil between occupants and all surface area that could contain fallout. Air should ideally be filtered, water should definitely be.
You have around 30 minutes after the blast before fallout hits the ground. Rain accelerates this. You can use the prevailing wind direction to judge whether you are downwind of a detonation. Ground detonations produce fallout, air detonations hardly do.
Lethal effects from a detonation is the initial, instantaneous flash, then pressure wave and explosive debris/structural failure that accompanies it, then radiation from fallout and radiation from ingested radioactive material.
This is a quick recap after reading this book some years ago.