Denver7 | Weather


Why is it colder in Denver than it is in the mountains? Cold air damming, explained

Here's why it's 10 to 20 degrees colder in town than it is in the high country.
Posted at 11:15 AM, Jan 13, 2024
and last updated 2024-01-13 13:15:27-05

Bitter cold has set in over most of Colorado, as many woke up to subzero temperatures Saturday morning

While many parts of Denver and the eastern plains will stay in the single digits before temps dive back below zero Saturday, much of the high country will see highs reach the teens and near 20 degrees.

So, how can it possibly be warmer at high-altitude than it is in town?

The meteorological explanation for this is a phenomenon called cold air damming. That’s when a mass of cold air becomes trapped on the windward side of a mountain range – in this case, the Front Range at the base of the Colorado Rockies.

Here’s the definition from the National Oceanic and Atmospheric Association:

The phenomenon in which a low-level cold air mass is trapped topographically. Often, this cold air is entrenched on the east side of mountainous terrain. Cold Air Damming often implies that the trapped cold air mass is influencing the dynamics of the overlying air mass, e.g. in an overrunning scenario. Effects on the weather may include cold temperatures, freezing precipitation, and extensive cloud cover

Our jetstream winds typically blow from the west to the east. In the case of this bitter cold, though, even if the surface wind is blowing east to west, the air mass is dense and heavy and has a hard time rising up the mountains into the higher elevations. That means the pocket of really cold air just sits over the lowest elevations while the warmer winds from the west blow over top of the Front Range.

The cold, dense, and shallow air mass can only be several hundred feet in depth, which means there can be major discrepancies in temperatures – and precipitation – over relatively short distances.
While it means colder temps in town, the clashing of those winds can mean immense snowfall for the mountains.

This weekend, the metro and plains could see a few inches of snowfall, primarily Sunday into Monday. Meanwhile, some areas of the high country will be measuring their snowfall in feet as several rounds of snow hammer the high country. As much as four feet could fall on some of the high mountain passes through Monday night, according to the National Weather Service.

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