A method of evaluating cloud-seeding operations is available in Oregon by the use of previously typed storm conditions. If cloud-seeding is effective in general, it must show similar departures under normal storm conditions. Thus previously typed storms are compared with similar storm types that passed through the Tillamook Burn area during the seeding operation of the summer of 1951.
* Present address: Dept. of Physics, Colorado School of Mines, Golden, Colo.