Fog in the San Juan Islands

October 23, 2010


Photographer: Rebecca Jones
Summary Author: Rebecca Jones; Jim Foster

The photo above showing a peculiar fog bank appearing to consume a mountainside was taken during a boat ride through the San Juan Islands in the state of Washington. Fog is not an uncommon commodity in the San Juan's. According to weather data from Friday Harbor, Washington, the daytime air temperature on this mid-September day was approximately 58 degrees F (15 C), and the dew point was 56 F (14 C). Once the surface air lifted over the low hills, it cooled adiabatically to, or below, the dew point temperature and condensed into fog droplets forming this upslope fog. Photo taken on September 19, 2010.

Photo details: Camera Maker: Canon; Camera Model: Canon PowerShot SX10 IS; Focal Length: 18.0mm; Aperture: f/4.5; Exposure Time: 0.020 s (1/50); ISO equiv: 200; Exposure Bias: none; Metering Mode: Matrix; White Balance: Auto; Flash Fired: No.