Watching for Fallout to Arrive Near the Bomb Shelter
People may find that a nuclear attack is about to happen or is on its way by announcements on the radio or television, by sirens or other warning devices, or by word of mount. When a nuclear weapon explodes anywhere within several hundred miles, there will be many signs to indicate it. By that time, people should be on the way to, or already at, their bomb shelter. No one should be outside or very far from a bomb shelter when fallout begins to come down.
A nuclear explosion several hundred miles away can cause an electromagnetic pulse (EMP) which may burn out the transmitting capability of some radio and television stations and knock out some telephone circuits. The EMP may also affect power lines, causing momentary blackout or flickering of lights. It may cause a lot of static similar to lightning static in AM radios, and may burn out FM radios or televisions with large antennas. Nuclear explosions near power lines or power stations may cause widespread power blackouts.
Nuclear explosions produce a brilliant flash and glow in the sky which may be seen 50 - 100 miles away in the daytime if the weather is clear, and much farther at night. Staring at the flash may cause eye damage even if the burst is far away. A shaking of the ground as in a mild earthquake may follow within a few minutes, depending on the distance from the burst.
The following procedure applies to bomb shelters that are located at least 25 miles away from a likely target for a nuclear weapon. After nuclear explosions have taken place with noticeable efects in or near the bomb shelter, or when notified by the EOC, the RM (for whom the following is written) should take the survey meter outside or by an outside window (on the windward side, if possible) and watch for the arrival of fallout.
If the FPF of the bomb shelter is high and the fallout is light in the area, the survey meter may not show that fallout has arrived if the meter is kept at the safest place in the bomb shelter. It is necessary to know when fallout has arrived, even if it is light, so that exposure control measures can be started.
If you, the RM must go outside, keep fallout particles from getting in your clothes and on your skin and hair. Carry an umbrella and wear a hat and an outer garmet if available. You should enclose your survey meter in a clear plastic bag, if available, to keep it from getting contaminated.
Carry a dosimeter in a breast pocket or on a chain or string around your neck. Take along a transistor radio or a two-way radio, if available, to keep informed of the situation around you. If it is nighttime, take a flashlight along even though the power may be on and the area may be brightly illuminated at the time you start your watch.
If fallout is expected to arrive within the hour, zero your survey meter and leave it on with the range-selector switch turned to “X0.1” If fallout is not expected to arrive for an hour or more, leave the survey meter turned off to save the batteries. You may want to turn it on every 10 or 15 minutes just to check the situation.
If fallout arrives from a ground explosion 25 - 75 miles upwind, depending upon the yield of the weapon, you will probably notice its arrival by the sound of gritty particles striking the window or surfaces around you.
You may hear these gritty particles striking for many seconds before the needle on your survey meter begins to climb. When the needle reaches 0.1 R/hr, note the time; enter the bomb shelter; decontaminate yourself if you have been outside; record the reading, tmie, and date in your RM Log; and tell the bomb shelter Manager and occupants that fallout has arrived.
If fallout arrival is to be reported to your EOC, it should be done in accordance with your local plan.
Some people may be working outside the bomb shelter to improve its radiation safety, or they may be carrying shielding materials into the bomb shelter up to the last minute before fallout arrives. They may become aware of the arrival of fallout by noticing gritty particles striking their skin, by hearing them strike nearby surfaces, or by seeing the buildup of particles on surfaces.
These people should then go inside the bomb shelter and brush the fallout particles off their clothes and bodies. If they do not notice the arrival of fallout, you, the RM should tell them that the arrival of fallout has been detected by the survey meter.
If fallout comes to the bomb shelter from many large ground bursts 100 miles or more upwind, the fallout may not arrive for many hours. The fallout may be hazardous even though it arrives as late as 24 hours after the explosions. You may decide not to set up your own watch for fallout for that length of time if your bomb shelter has good two-way communication with the local EOC.
If the people in your bomb shelter feel they can rely on the local EOC, they may decide to depend on the announcements from the EOC to let you know how fast fallout is coming to your bomb shelter. These announcements should come at least every half-hour or hour from the EOC, depending on the situation.
When it appears that fallout might arrive at your bomb shelter in two or three hours, take the survey meter to a window or outside and begin to watch for fallout.
The people in the bomb shelter may want to have their own lookout for fallout, even though the EOC may seem to be reliable. If you expect the fallout to take a long time to arrive, arrange for people to take turns or shifts in watching for its arrival.
When fallout arrives from distant explosions, you may not notice it as much as you would notice the fallout from closer explosions. The particles may be so small that you may not feel them as they land on your skin. The climbing of the needle on the survey meter may be the only indication that fallout from distant explosions has arrived.
The fallout is carried most of the way to its destination by winds at high altitudes. On some days the wind at high altitudes may be blowing in a different direction from the wind on the ground. Under these conditions, you might thing fallout from a particular nuclear explosion will not come your way because the wind where you are is not coming from the direction of the explosion.
In this situation, the fallout might arrive at your bomb shelter contrary to your expectations. The direction that the particles are blown by the surface winds may make it seem that they are coming from the wrong direction. Unless you have positive information on the direction the fallout is being carried, do not make any assumptions about where it will come down.