The present Portland airport located on Swan Is. in the Willamette River is to be moved in the near future to the larger and more spacious Portland Columbia Airport on the Columbia River. Since terminal forecasts will soon be made for this new airport, comparative weather conditions, especialy fog, are of interest.
In the study, Portland Columbia was found to have 31% more hours per year with visibility equal to or less than ½ mile, and also slightly more hours with ceilings equal to or less than 600 feet. This makes Portland Columbia somewhat less favorable for airline operations. Portland Columbia also has 23% more days per year, on the average, with visibility equal to or less than ½ mile and/or ceilings equal to or less than 600 ft. However, the strong easterly winds of the Columbia River Gorge are a factor which frequently keep Portland Columbia relatively fog free while Swan Is. has dense fog.
Portland Columbia airport has the advantage of being so located as to have considerably less city smoke, and because of this, less hours of instrument weather.
*Paper read at Seattle Meeting, June, 1940.