Terrain plays an important role in the weather of southern Colorado, and this region is no exception. With several 14ers, a huge valley, several smaller mountain valleys and other important terrain features creating many micro climates that have their own unique weather, this is a challenging area to forecast for.
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.