Lake Wanapitei Winter Evaporation Fog

April 09, 2011

Photographer:Blaine Nicholls
Summary Author: Blaine Nicholls

The photo above shows a stream of fog emanating from a fissure on ice covered Lake Wanapitei, in the City of Greater Sudbury, Ontario, Canada. Evaporation fog is commonly seen in late autumn as "steam fog" hugging the surface of a river or a lake. When cooler, drier air moves over the still warm water, evaporation from the warm water saturates the cooler air, thus forming wisps of rising fog. Less frequently observed is evaporation fog over a frozen lake. As river or lake ice contracts and expands during the winter season, cracks and ice ridges are formed. This particular fissure was sufficiently deep to expose the relatively warm water beneath the approximately eight inch (20 cm) thick ice layer. When the newly exposed water evaporates, the much colder air (-22 F or -30 C) quickly freezes the emerging vapor into ice fog. Lake Wanapitei formed from an asteroid impact 37 million years ago. Photo taken on the morning of January 20, 2011.

Photo details: Camera Maker: NIKON CORPORATION; Camera Model: NIKON D700; Lens: 70.0-200.0 mm f/2.8; Focal Length: 200mm (35mm equivalent: 200mm); Focus Distance: Infinite; Aperture: f/16.0; Exposure Time: 0.0013 s (1/800); ISO equiv: 800; Exposure Bias: -1.00 EV; Metering Mode: Matrix; Exposure: shutter priority (semi-auto); White Balance: Manual; Light Source: Cloudy; Flash Fired: No; Orientation: Normal; Color Space: sRGB.