—-k-— Most fallout prediction models require as input rather detailed specification of the total amount of fallout ana the distribution of activity as a function of particle size and height in the initial stabilized radioactive cloud. Te more simplified method currently employed is a scaling technique which does not require explicit definition of the distribution of activity as a function of particle size and height in the initial cloud. Rather, the assumption is made that an appropriate analog event can be chosen whose particle size-activity distribution will adequately approximate that of the event for which a prediction is being made. The scaling method consists of a ratio technique whereby the parameters which determine hotline fallout . intensities and the location of these fallout intensities in their respective fallout patterns are related, and then used in conjunction with the empirical results of o previous event for prediction purposes. Exposure rate levels are normalized to one hour after the detonation at all downwind distances to account for radioactive decay. provide predictions of: This technique is used to (a) external gamma exposure from deposited activity alone the fallout hotline; (d) external gamma exposure along the hotline fran immersion in the passing radioactive cloud; and (c) dose to the thyroid potentially resulting from ingestion of I-131 contaminated cow's milk, again, along the fallout hotline. The form of the scaling equations, where the unprimed symbols refer to the analog event and the primed symbols refer to the forthcoming event, are as follows: ‘= ot teeta eee o\Vn\ 2 fy\2 sty’ -