Abstract
When dense steam fog occurred along the rivers in Asahikawa, Hokkoidô, in winter, the fog was seeded with the silver iodide nuclei by means of a new type silver iodide generator and the growth of ice crystals in the fog was observed.
Various forms of ice crystals were produced, and among them plates were most predominant. A relatively small number of columns and capped columns were also found. Many steller crystals were formed on March 14, when the weather conditions were supposed to be favorable for the growth of these crystals.
The observed size showed a good agreement with the value predicted by Houghton within about 150 m from the generator, but at larger distances from the generator the size became smaller than the predicted one. This probably suggests that larger crystals had fallen upon the ground through the shallow fog layer before they were carried to distant places.
