The capability of dissipating supercooled fogs by aircraft seeding has been recognized since Schaefer experimented in 1946. Except for some localized application of this weather control and some side effects of research aimed at precipitation increase, no organized program of airport weather improvement was established in the United States until 1963. Seeding of supercooled fogs by dry ice was organized during two winters for the purpose of increasing airline schedule reliability at airports subjected to this cold fog. Better than 80% success was attained by this method, resulting in the operation of approximately 200 scheduled flights which would otherwise have been canceled. Typical examples of visibility improvement after less than an hour of seeding are illustrated. The direct benefits resulting from these programs outweigh the costs significantly and suggest that similar fog dispersal operations should be expanded to other areas of the United States which are subjected to supercooled fogs.

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