Early History -11 ■ 



On November 21 Schaefer seeded a supercooled valley fog with dry 

 ice. He found that it was possible to reduce visibility by generating more 

 ice crystals than fog droplets and also to dissipate the fog by dispensing 

 just enough ice crystals to use up the fog droplets, each crystal growing 

 large enough to fall to the ground, 



OTHER EARLY FLIGHTS 



There were two other seeding flights made by Schaefer with a rented 

 plane that month, one on the 23d and the other on the 29th/ '^' These tests 

 were made on isolated cumulus -type clouds. The whole of each cloud was 

 changed into ice within five minutes , and snow began falling from the base 

 of the cloud. 



Photographs were taken from the ground every 10 seconds, and these 

 were developed and projected as movies. They showed that, with orographic 

 clouds the air moves into one part and leaves another part; in a matter of 

 five minutes or so an entirely new mass of air is within the cloud,. Thus 

 it was found that experiments with small cumulus clouds are usually of 

 little interest, for the effects last but a few minutes. 



Another flight test was made on December 20, also using a rented 

 plane/ ' This time the sky was completely overcast, and by 9 o'clock 

 in the morning the Weather Bureau in Albany reported that it expected 

 snow by 7. o'clock that evening. Schaefer dropped about 25 pounds of 

 granulated dry ice in the lower part of the cloud at a rate of 1 to 2 pounds 

 per mile, about 1000 feet above the irregular and ragged base of the over- 

 cast, at altitudes ranging from 7000 to 8500 feet, at about noontime. A 

 two -pound bottle of liquid carbon dioxide was also discharged into the 

 cloud during this period. 



Before and during the seeding flight, a light drizzle of supercooled 

 rain had been encountered, which seemed to evaporate before it reached 

 the ground. Flying back along the line of seeding, after seeding was com- 

 pleted, it was found that the drizzling rain had stopped and that it was 

 snowing. But on reaching the point where the seeding had stopped, drizzle 

 conditions were again encountered. Three more seeding runs were made 

 along the same line before the plane returned to Schenectady. 



The plane then descended to 4000 feet, where the visibility was 

 better, and made a reconnoitering flight, checking the places where snow 

 was falling. By this method and through reports received, it was found 

 that snow started to fall in many places in the region. At 2:15 p.m. it 

 started snowing in Schenectady and at many other places within 100 miles. 

 It snowed at the rate of about one inch per hour for eight hours, bringing 

 the heaviest snowfall of the winter. While the seeding group did not 



