IT'S
Complex
We live in a part of the world that has rapidly changing weather. We sometimes try to understand it. Mostly we just enjoy it.
Briefly:
-
WHICH WAY THE WIND ?
Light, Variable, Directional
up slope - down slope
round and round
a bit confusing
- It's often heard in the
neighborhood: "Yellowstone Makes It's Own Weather."
Well - sorta does and sorta doesn't.
The Yellowstone Plateau, fortuitously situated at the eastern end of the Snake River Plain, abruptly interrupts the prevailing winds. The difference in elevation between the plain and the peaks of the plateau is about a mile, (Pocatello, Idaho=4,462, Mt. Washburn=10,243.)
.. The gradient along this stretch of the Rocky Mountains is fairly steep and the winds, having been funneled down the Snake River Plain for about 260 miles must do something with an abrupt change in elevation covering just 35 miles or so.
.. The neighborhood weather guru uses the term "Adiabatic Process." [Say that 10 times as fast as you can.]
.. As we understand it: the air rushing up slope or down slope changes temperature and pressure rapidly, (remember that this is a big plateau, not just a mountain.) As simply as he could explain it to us was:
Adiabatic cooling happens as air mass expands with increasing elevation (because density of gases decreases farther into the atmosphere). As elevation increases, the air gets cooler because energy is drawn from the surroundings. Less dense air traps less heat resulting in this net cooling called adiabatic cooling. It occurs at an average of 6 degrees Celsius per 1000 meters, but it can vary.
.. And, he says, conversely - heating happens as the winds rush down slope. Sounds simple enough - BUT!
.. The mountains surrounding the central part of Yellowstone National Park, (where the caldera has influenced the topography,) are considerable in their elevation.
.. This causes complications in the simple understanding. The adiabatic process also occurs on the slopes of the mountains. That means, (in the simplest terms - which is what we need,) that there are a myriad of cooling and heating, (and pressure changing,) regimens within the Yellowstone Plateau.
.. On the western edge of the plateau are mountains like Two Top=8,500, Lions Head=8,700, Lone Peak=11,166. Turbulence swirls around these mountains before the wind even gets to the Yellowstone Plateau.
.. Then there are the mountains in the park and around it's periphery in other directions: Electric Peak=9,459, Bunsen Peak=8,527, Mount Washburn=10,243, and so on
.. And, of course, there are the mountains to the west, south and north of West Yellowstone. With all the up and down and round-and-round it's no wonder that we have such rapidly changing weather. -
THE HISTORIC AVERAGES
Clouds Seen In Our Neighborhood
- Other Fine Stuff : coming soon.