(SOUTHERN COLORADO) — From the Pikes Peak Region to the Foothills and Southeast Plains, to the Mountains and Valleys, terrain has a big impact on the weather the FOX21 Storm Team forecasts in a particular area.
Below is an explainer of each region and its terrain impacts on weather.
Pikes Peak Region
You can thank the terrain for the rapid changes in weather often seen during the winter and the thunderstorms that form in the summer. The Pikes Peak Region ranges from 14,115′ on top of Pikes Peak to 5,095′ along Black Squirrel Creek on the El Paso/Pueblo County line.
As a result, the slopes of Pikes Peak, including the Colorado Springs metro area, get more lightning strikes each year than other locations in Colorado. On average, between four and six lightning strikes occur in each square kilometer of this region each year.
Pikes Peak plays an important role during the winter. The additional lift created as storms run into the Peak can produce several feet of snow above the tree line, sometimes closing the Pikes Peak Highway. Wind directions into the peak will typically produce enhanced areas of snow on the upwind slopes, while the downwind slopes will be “shadowed” and receive lighter amounts of snow. This changes from storm to storm and is an area of focus for the FOX21 Storm Team.
The Palmer Divide, sometimes called Palmer Ridge, creates areas of rising and sinking air that play an important role in the weather along Colorado’s Front Range.
The Palmer Divide is the hill you drive over on I-25 between Colorado Springs and Denver. It separates the Arkansas River valley in Southern Colorado from the South Platte River valley in northeast Colorado.
Rising to 7,700′ in Black Forest, the divide is a significant terrain feature for weather during both the winter and summer. It’s a really big hill when you compare Denver’s elevation of 5,280′ and downtown Colorado Springs which sits at about 6,000′. It provides enough lift that it enhances snow amounts during the winter and helps to develop thunderstorms in the summer.
The differences in weather across the Pikes Peak region because of the terrain features in the area can be incredible. During classic high plains blizzards with strong north wind, parts of the Palmer Divide and the northern slopes of Pikes Peak can have 1′-2′ of snow with 5′-8′ drifts, while downtown Colorado Springs, less than 18 miles away, has only an inch or two of snow.
Mountains and Valleys
San Luis Valley
The San Luis Valley is typical of a major valley surrounded by mountain ranges. The central section of the valley can often be left out of precipitation events as the surrounding mountains maximize lift in the atmosphere and get the bulk of the moisture. During the winter months, cold, dense air often becomes trapped on the valley floor for days or weeks at time. This produces extended periods of very cold conditions, and this can help make the valley the coldest part of the country.
The Wet Mountains usually flex their muscles during winter storms when the wind is out of the northeast. During these situations, if certain atmospheric conditions are right, the eastern slopes of this range can get dumped with feet of snow. It isn’t uncommon for Rye and Beulah to have two feet or more of snow in what otherwise is a pretty normal winter storm.
The orientation of the long Sangre de Cristo Range can help to create mountain waves during the cooler months. Mountain wave clouds that wouldn’t exist without this terrain feature can make temperature forecasts quite challenging. Mountain waves can also play a role in downslope wind storms.
Foothills and Southeast Plains
During the summer months, the river valley helps act as a channel for low-level moisture from the Gulf of Mexico. This moisture pushes up the slopes of the Sangre de Cristo range, the Wet Mountains and the Raton Mesa to help develop thunderstorms.
The elevation difference between the mountains and the plains in this region helps to create a typical daily wind pattern. Winds at lower elevations blow from the plains toward the mountains during daytime and from the mountains toward the plains at night. The mountain-plains wind system is most apparent on individual days when skies are clear and the general prevailing winds are weak, but it is also seen in climatological averages.
Downslope Wind Storms
The orientation of the Sangre de Cristo and Wet Mountain ranges are favorable for the creation of mountain waves during the cooler months of the year when the atmosphere tends to have more stable layers in it. These mountain waves are created when stable air moves up and over the mountains.
The creation of mountain waves are quite complex, but there are two types of mountain wave downslope windstorms. The warm (Chinook), pre-cold front type tends to be more localized for the strongest gusts as the crest of the mountain wave reaches the ground whereas the cold (Bora) type occurs behind a cold front and tends to impact a wider area.
Interesting temperature variations can occur across this area during when extremely cold airmasses from the Canadian plains or the arctic back into eastern plains of Colorado. This very cold and dense air will find the lowest possible spots as gravity acts on it, very much like water in a bowl. As you can see in the topographic map above, the Arkansas River valley is the low spot from west to east across this area. It isn’t uncommon for mountain areas to be warmer than the lower valleys or the plains during the winter months. These inversions can be quite stark, sometimes a 40-degree difference or more!