Advection Fog
Radiation Fog



Radiation Fog

During the cloudless nights the ground of the valleys below the Pulpit Rock cooled so much down that radiation fog was formed (ValleyFog2.jpg). Additionally there were sources of water vapour, because near Villach and Klagenfurt a river and several lakes are located in the valley. However the stratus layer covered a much larger area than just the lakes. Because of the calm air it can be assumed that the radiation fog had also been formed without any humidity source at the ground. During the forenoon the fog cover raised more and more (ValleyFog1.jpg and ValleyFog3.jpg) until the vantage point disappeared also inside the fog layer (Fog1.jpg, Fog3.jpg and Fog7.jpg).


In ValleyFog4.jpg and ValleyFog5.jpg the fog arose only above the valley and not further away from the humidity source, the river "Kyll", which is situated in the valley in front of the mountains. In the case of the valley fog in Carinthia (see above) the air was cooled down by infrared emission during the night. This resulted in super-saturation and therefore cloud formation. In contrast the valley fog in Gerolstein arose, since the air was super-saturated by humidification. Further possibilities to reach super-saturation are described in Advection Fog, Isobaric Mix Clouds and Mix Clouds II.

ValleyFog1.jpg to ValleyFog3.jpg, Fog1.jpg to Fog7.jpg: S. Borrmann, Pulpit Rock, Carinthia, Austria, December 2002

ValleyFog4.jpg and ValleyFog5.jpg: Tamara Borrmann, Gerolstein (Youth Hostel), Eifel, Germany, 12 June 2005, 1:00 p.m.