photo #7843729

The air temperature was –15ºC (6ºF) when Kathleen Janick (Member 49,856) braved the weather to spot these smouldering wisps of fog curling off the Atlantic Ocean at Cape Elizabeth, Maine, US. This type of fog, which occurs over bodies of water, is known as sea smoke. It is a rare winter event, requiring a sudden cold snap along the shore when frigid air drifts out over warmer water. On this day, the water was a very chilly 8ºC (46ºF), but that was still warm enough compared to the air temperature to set the fog swirling. The water’s surface warmed the low air in contact with it just enough to set it rising and to fill it with moisture as the water evaporated. This subtle movement carried the water vapour up through the frigid air above, where it cooled, and the moisture condensed right back into tiny droplets appearing as curling tendrils of sea smoke. This is the same effect as the steam rising from a hot cup of tea, which is doubtless what Kathleen was looking forward to once she got back indoors.In addition to sea smoke, this brisk winter cloudscape includes a billowing tier of Stratus fractus and distant Altocumulus.