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Vail Valley weather defies forecasts

Jaymee Squires
Gore Range Natural Science School
Vail, Co Colorado
Jaymee Squires
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VAIL, Colorado ” Living in the mountains in Colorado’s Vail Valley, we all learn that you can’t really depend on the weather forecasts. How many times have you heard forecasts of “up to three feet of snow in the northern and central mountains” and gone to bed dreaming of fresh powder runs? Maybe you even started a slight cough at work the previous day, laying the groundwork for calling in “sick.”

When you wake-up, though, there’s not a flake in sight and you wonder what went wrong?

So why is forecasting weather in the mountains notoriously unreliable? Is it the meteorologists? Are they just inept? No, meteorology as a science has advanced tremendously during the past few decades, enabling us to forecast the paths of deadly storms like hurricanes and recognize the conditions likely to produce tornados or blizzards (at least sometimes).



The fact is that weather is tremendously difficult to predict, partly due simply to the size of it all ” try to imagine predicting the behavior of an air mass that is large enough to cover four to six states (and I mean big, Western states, not those tiny ones they cram into the northeast.)

Weather is created as air flows across the earth’s surface. As it moves, it develops characteristic properties of temperature and moisture that then affect the type of weather it will bring. Sounds simple so far, right?



As the air mass flows across the surface of the earth, it is influenced by that surface. Factors such as the amount of incoming solar radiation, the amount of heat reflected or absorbed by the surface, the amount of moisture present, and numerous others all interact to affect the passing air mass. In addition, air masses can also collide, further complicating the interplay of factors influencing weather patterns.

Weather prediction in the mountains is complicated, in part, by the fact that the land over which the air masses flow is tremendously varied. The altitude, shape, steepness, and even the presence of vegetation can all affect how air masses flow over, around, and through mountainous areas.

In addition, conditions such as the speed and stability of the air masses also influence whether an air mass will rise up and over a mountain range, dropping moisture (orographic lift), or whether it will simply split and follow the contours of the land. Sometimes even small-scale influences from a single mountain valley can noticeably alter larger patterns of moisture, temperature, and movement.



In short, mountains are affected by weather, but they can also dramatically change, or even create their own weather patterns.

If you imagine even trying to compile data such as that mentioned above from every mountain ridge, peak, and valley at every moment of every day, you might begin to understand the enormity of the task of predicting mountain weather. The inaccessibility of mountainous regions simply makes it nearly impossible to set up enough weather stations to gather meaningful data. Even satellites cannot gather enough accurate data from mountain peaks and valleys due to the uneven terrain and limits on space and time.

This creates an information gap in mountainous areas, just where scientists need more data to understand the complex interactions of air flow dynamics and terrain on weather patterns.

Despite the odds that are stacked against them, forecasters continue to compile and analyze meteorological data in an attempt to give us the predictions we so desire. In the U.S., much of the raw weather data is delivered to Unidata, a quasi-governmental research corporation located in Boulder, Colorado.

Unidata analyzes and provides the readable data, along with software to help further analyze it, to meteorologists and research institutions throughout the nation. Local forecasters use this data, combined with knowledge about the local mountains and climatology to come up with a local prediction. However, the low population and remoteness of mountainous areas like ours is a deterrent for large-scale investments in data-gathering and analysis.

Besides, by the time the tremendous number of factors affecting the air mass has been figured out, the air mass and its weather might be long gone anyway.

The only thing you can be sure of with regard to Colorado weather is that it will be changing soon. It may not be snowing out my window, but it’s probably snowing somewhere.

Jaymee Squires is the graduate course instructor at the Gore Range Natural Science School. Gore Range Natural Science School’s “Nature Notes” will appear regularly in the Vail Daily. The Science School’s mission is to awaken a sense of wonder and inspire environmental stewardship through natural science education. Visit http://www.gorerange.org for program listings and information regarding the future Environmental Learning Center on the Buck Creek Campus.


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