An ice fisherman sets to work on Monona Bay in Madison, Wis.
Q: Why does fog form over the lake?
A:Â Fog is essentially a ground-hugging cloud, composed of tiny liquid water droplets.
This particular fog, called a steam fog, forms when cold air drifts across relatively warm water. The lake water evaporates into the air above the lake surface. The lake must be unfrozen.
The air is cooled and moistened, causing the dew point to increase. As the dew point approaches the air temperature, condensation occurs, forming fog droplets.
The condensation further warms the air. The warmed air rises and mixes with the cold air above it, reaching saturation and causing more fog to form.
When there is a large difference in temperature between the air above the lake and the water at the surface of the lake, there will also be considerable turbulence in the air over the lake.
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The combination of steam fog production, turbulence over the lake, and strong winds can create one of nature’s most awesome spectacles — steam devils.
The name was first used in 1971 after observations over Lake Michigan.
Steam devils are swirling columns of steam fog (analogous to dust devils) that look like a whirlwind of steam fog on a cold day. Steam devils can rise up to 1,500 feet above the lake.
One of the many features of living near large lakes is that they are often shrouded in a fog in the fall and early winter.
10 years after Superstorm Sandy: Rebuilding the infrastructure
A chain link fence blocks access to a section of the East River Park as construction continues on the East Side Coastal Resiliency Project, Friday, Oct. 7, 2022, in New York. After Superstorm Sandy struck the northeast U.S. in 2012, an unprecedented effort began to fortify the densely populated coastline against the next big storm. Then, last year, the region learned that even all those precautions might not be enough in an age of more powerful storms.(AP Photo/Mary Altaffer)
Framed by the Manhattan bridge and the downtown skyline, construction continues on the East Side Coastal Resiliency Project at the East River Park, Friday, Oct. 7, 2022, in New York. (AP Photo/Mary Altaffer)
Reinforced concrete pipes sit at the construction site of the East Side Coastal Resiliency Project at the East River Park, Friday, Oct. 7, 2022, in New York. (AP Photo/Mary Altaffer)
Heavy duty construction equipment are seen at the construction site of the East Side Coastal Resiliency Project at the East River Park, Friday, Oct. 7, 2022, in New York. After Superstorm Sandy struck the northeast U.S. in 2012, an unprecedented effort began to fortify the densely populated coastline against the next big storm. Then, last year, the region learned that even all those precautions might not be enough in an age of more powerful storms. (AP Photo/Mary Altaffer)
A section of the underground drainage system is visible during construction at a "resiliency park" in Hoboken, N.J., Wednesday, Oct. 19, 2022. Hoboken has built two such parks, designed to flood during storms by capturing water that would otherwise flow into the streets and sewer systems, with three others to come. They can hold millions of gallons of storm water, including through the use of large underground cisterns, one of which is the size of a city block. (AP Photo/Seth Wenig)
Construction crews work to complete a "resiliency park" under construction in Hoboken, N.J., Wednesday, Oct. 19, 2022. Hoboken has built two such parks, designed to flood during storms by capturing water that would otherwise flow into the streets and sewer systems, with three others to come. They can hold millions of gallons of storm water, including through the use of large underground cisterns, one of which is the size of a city block. (AP Photo/Seth Wenig)
Liz Ndoye poses for a picture on her street in Hoboken, N.J., Wednesday, Oct. 19, 2022. Ndoye's basement and street were flooded during Superstorm Sandy ten years ago. (AP Photo/Seth Wenig)
Sand covers a sign on the beach near the Manasquan Inlet in Manasquan, N.J., Thursday, Oct. 20, 2022. After Superstorm Sandy struck the northeast U.S. in 2012, an unprecedented effort began to fortify the densely populated coastline against the next big storm. Then, last year, the region learned that even all those precautions might not be enough in an age of more powerful storms.(AP Photo/Seth Wenig)
Houses line the beach in Manasquan, N.J., Thursday, Oct. 20, 2022. For houses along this section of the New Jersey shore, back-bay flooding, from water entering the inlet, can be as much of a concern as ocean surges during large storms. (AP Photo/Seth Wenig)
An amusement park sits next to the ocean in Seaside Heights, N.J., Thursday, Oct. 20, 2022. The Jet Star roller coaster, whose collapse into the ocean at Seaside Heights, N.J. during Sandy provided an iconic image of the storm's destruction, has been replaced with a new ride, built on the beach instead of over the water like its predecessor. (AP Photo/Seth Wenig)
A boat enters the Manasquan Inlet in Manasquan, N.J., Thursday, Oct. 20, 2022. One proposed solution to flooding is a $16 billion plan by the U.S. Army Corps of Engineers to address back-bay flooding along the Jersey Shore - a major source of damage during Sandy that was overshadowed by oceanfront flooding. It would build storm surge gates across the mouths of major inlets, like Manasquan, and install similar gates in the middle of bays to stop waves from surging across the waterway into homes. (AP Photo/Seth Wenig)
Chairs sit arranged on a high berm that separates the ocean from oceanfront homes in Mantoloking, N.J., Thursday, Oct. 20, 2022. (AP Photo/Seth Wenig)
An amusement park sits next to the ocean in Seaside Heights, N.J., Thursday, Oct. 20, 2022. The Jet Star roller coaster, whose collapse into the ocean at Seaside Heights, N.J. during Sandy provided an iconic image of the storm's destruction, has been replaced with a new ride, built on the beach instead of over the water like its predecessor. (AP Photo/Seth Wenig)
A view of lower Manhattan from Hoboken, N.J., Thursday, Oct. 20, 2022. After Superstorm Sandy struck the northeast U.S. in 2012, an unprecedented effort began to fortify the densely populated coastline against the next big storm. Then, last year, the region learned that even all those precautions might not be enough in an age of more powerful storms. (AP Photo/Seth Wenig)
"Weather Guys" Steve Ackerman and Jonathan Martin are professors in the University of Wisconsin-Madison department of atmospheric and oceanic sciences.