Vail Daily column: Colorado weather’s only constant is change |

Vail Daily column: Colorado weather’s only constant is change

Drew Foulis
Curious Nature

This winter has been characterized by dumping snow, super cold temperatures and relatively clear skies. Great news for farmers, ski resorts and the wild locals, but bad news for the backcountry skiers. The quick build-up of snow mixed with sustained cold temperatures makes for a weak snowpack, and we’ve already seen some of the dangers this can create.

There is way more to Colorado’s weather than just base accumulation and snowpack. Only a few generalizations can be made for the state as a whole, where the climate is usually sunny with warm summers and cool winters. The only thing you can always count on weather wise is changing conditions. To start, we need to define a couple of terms. Weather is the current conditions at a certain place and time while climate is the weather conditions prevailing in an area during a long period of time.

Coastal climates are regulated by large bodies of water, but our location in the center of the continent makes us very vulnerable to changing conditions. Local climates are also greatly affected by elevation and the positioning of mountains and valleys. Bluebird days can turn stormy in less than an hour and clear up just as quickly. A testament to the variability of conditions in the Centennial State is the difference between the average temperature on Pike’s Peak and the average temperature of Las Animas, 115 miles southeast, which is about 35 degrees Fahrenheit! That is the same as the average temperature difference between Iceland and southern Florida. These discrepancies are largely caused by differences in elevation. As a good rule of thumb, the ambient temperature will drop about 3 degrees Fahrenheit for every 1,000 feet of elevation gained. This is what makes our mountain tops and high valleys so cold.

There are two main weather patterns that cause snow to fall in Colorado. We have the eastern moving air masses that are lifted up as they cross the mountains, wringing out the moisture as they rise in a phenomenon known as orographic lifting. On the Front Range, occasionally there will be a northwesterly moving air mass that mixes with cold air coming from the Rockies and dumps snow on the eastern slope. There is another occurrence that happens in the high valleys and mountain passes called an inversion that is caused when cold dense air from up high in the mountains rushes down into the valleys to replace the rising warm air. These inversions sometimes trap cold air in the valleys for days or weeks at a time.

Another seemingly anomalous occurrence is what locals call “valley wind.” This is when air seems to move from the mountains down into the valley in the morning, and then switches directions in late afternoon. This is caused by uneven heating of the land surface in the high Rockies.

Weather has a profound effect on our daily lives. Whether we are tilling the fields or making turns, the weather determines if we will be shredding pow or shedding layers, and it can make a day go from shralping the gnar to scraping your windshield in no time. Regardless of what you do or where you do it, the unpredictable and variable nature of Colorado weather is part of what make living here so interesting.

Drew Foulis is a winter naturalist, recent native and dishwasher here in the Eagle Valley, who spends most of his time living the dream and the rest of the time dreaming about it.

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