In Time of Emergency by United States. Office of Civil Defense (classic books for 10 year olds .txt) 📕

nts, weather conditions and other factors. There isno way of predicting in advance what areas of the country would beaffected by fallout, or how soon the particles would fall back to earthat a particular location.

Some communities might get a heavy accumulation of fallout, whileothers--even in the same general area--might get little or none. No areain the U.S. could be sure of not getting fallout, and it is probablethat some fallout particles would be deposited on most of the country.

Areas close to a nuclear explosion might receive fallout within 15-30minutes. It might take 5-10 hours or more for the particles to driftdown on a community 100 or 200 miles away.

Generally, the first 24 hours after fallout began to settle would be themost dangerous period to a community's residents. The heavier particlesfalling during that time would still be highly radioactive and give offstrong rays. The lighter particles falling later would have lost much oftheir radiation high in the atmosphere