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Cold Air Damming – What You Need to Know

8 Nov 2017, 9:54 am

Cold air damming, or CAD, is a really complicated equation but it’s also a meteorological phenomenon that often results in stretches of cold and damp weather that can sometimes last up to 10 days. It can also result in dangerous ice storms!

But what exactly is it?
Where does it happen?
and when does this phenomenon usually happen?

Essentially, Cold Air Damming is an event typically seen from October to April in numerous areas around the Country. This includes the Pacific Northwest, the Southwest and more commonly CAD events are found east of the Appalachian mountains.

Here’s how it works:


During the winter months – cold high pressure systems swing in from Canada. When this cold high pressure moves east of the Appalachian mountains, which by the way is a north/south oriented mountain range, the cold air tends to dam, pool or bank up against the leeward side of the mountains. This happens due to the fact that the flow around an anit-cyclonic system (High pressure) is clockwise.

During the winter months, typical atmospheric conditions generally set up to where moisture from the Gulf of Mexico collides with this pocket of cold air. This sometimes leads to significant weather events likes snow and ice storms across the Carolinas and the Mid-Atlantic.

So as we continue though the winter season – keep an ear open for th term “Cold air damming” and remember that it typically means that there is cold air and winter-like weather on the way.

For WeatherNation: Meteorologist Andy Stein 

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