India, Dec. 9 -- Large parts of the United States have come under the grip of freezing fog - a phenomenon where droplets formed by fog can freeze instantaneously due to surface temperatures being below zero.

According to Newsweek, the National Weather Service (NWS) issued warnings about freezing fog for several cities in Maryland, North Carolina, Washington, DC, and Virginia this past Sunday.

As per the NWS' website, freezing fog can also lead to the formation of black ice on roadways, which is hard to spot. This could make driving very risky as the roads can get slippery. It can also cause danger to flights if thin sheets of ice envelope the plane.

On Sunday, the NWS warned of visibility being restricted to "one quarter mile or less."...