National Geographic : 1924 Jul
THE NATIONAL GEOGRAPHIC MAGAZINE WHERE THE AIR MAIL LANDS AT ROCK SPRINGS, WYOMING The town is in the foreground and the air mail landing field is in the upper right corner. It was upon the slope in the upper left corner that the mail plane shown on page 114 crashed. and in the mountains and high elevations that we would cross in darkness. The moon became noticeable about October 28, and from this date the fore casts were watched very closely. How ever, the weather at this period was ex tremely unfavorable throughout the entire route, making a start impracticable. A study of weather conditions during the period of waiting in San Diego dis closed the fact that a very important fea ture had been overlooked. It was very true that an average wind velocity from west to east of 22.5 miles per hour pre vailed during the fall, but other unfavor able elements were combined with this factor, entirely obliterating its value as a beneficial agent. Winds blow in to fill up an area of low pressure and blow out from an area of high pressure. An area of low pressure is usually a storm center, while an area of high pres sure indicates good, clear weather. These areas usually drift, with various deflec tions, in a general direction from west to east. Strong winds of great velocity blow into the low-pressure area, or storm center. A favorable wind for the trans continental flight would be one blowing into a storm, and a head wind would occur, with good clear atmosphere, as a result of the high pressure. Winds blow in a counter-clockwise direction about a low-pressure area and in a clockwise di rection about a high-pressure area.