The Better Part of Valor…
There is a LOT of incredibly useful flying wisdom boiled down into pithy one-liners. Last weekend, one of those one-liners was spot-on….
On short notice, my wife and I planned a weekend personal trip to Colorado while our kids were out of town. For days before the flight, the predicted weather looked spectacular. From Houston (SGR) to Eagle/Vail (EGE), there wasn’t to be a cloud in the sky, and a high pressure system would sit lazily over southern Colorado the whole time. At first, this looked like a perfect opportunity not only for us to have a great weekend, but for me to do one of my favorite things, fly the mountains.
But as the planned Thursday departure approached, the forecast got angrier. The MOS (Model Output Statistics, or a method of processing weather forecast models to output useful aviation weather predictions) for the Eagle/Vail airport upped the predicted Thursday afternoon surface winds to over 25 knots, with even stronger winds ripping over the tops of the Rockies. Instead of just soaring off into clear blue skies, I had to actually think about the weather….
The quicker route to Eagle/Vail — over the Rockies — follows the Arkansas River valley, overflies Leadville, and crosses Tennessee Pass to approach Eagle Vail from the east. A longer route skirts the mountains, south of Santa Fe and Durango, and approaches Eagle/Vail from the south. The longer route was starting to look much better, because when it gets windy around the mountains, it gets bumpy. Sometimes, absurdly bumpy.
Houston to Vail: over the mountains…
Houston to Vail: around the mountains…
Turbulence comes in many shapes and sizes. Perhaps the two predominant types are clear air turbulence (CAT) and mountain wave turbulence (MTW). CAT is turbulent movement of air masses without visual clues, usually formed when bodies of air meet moving at different speeds as a result of temperature/pressure gradients. MTW is a type of mechanical turbulence: when wind blows across the mountains, it’s disturbed, much like a running stream eddies as it flows around rocks. Usually turbulence is safe, just annoying and uncomfortable to the pilot, and uncomfortable and sometimes unnerving to passengers. But in very limited (and usually avoidable) circumstances — such as rotor turbulence — it can be dangerous.
By Wednesday afternoon, the forecast for Thursday for either route to Eagle/Vail prophesied a miserable flight at any available altitude. The CAT and MTW forecasts advertised at least moderate turbulence (“definite strains against seat belts”) for half of the 5-hour flight. We’d spend much of the flight downwind of the mountains, exactly where MTW churns up the air. On top of that, a dramatic temperature lapse rate (the rate at which the temperature falls with altitude) would add insult to injury. The popular Foreflight app literally spelled it out: “Rapid temperature drop: possible unstable air.”
My wife Stacy leaves the flight planning to me, but at one point Wednesday afternoon she popped her head in and asked, “How’s the weather look?” She was planning our weekend hikes and had noticed that Eagle County had upped its fire restrictions on account of high winds.
Although Eagle County’s supercharged fire restrictions were irrelevant to our flight, they were probably the last straw for me. I LOVE flying in the mountains. But, after all, this was supposed to be fun. And spending the next 24 hours trying to guess where it would only be moderately turbulent, and then at best being heaved against our seat belts for a couple of hours, was not going to be fun. So, we bailed on our mountain flying. Instead, we booked a ride to Denver on “The Company Plane” and rented a car to drive across the mountains.
After our bumpy 737 ride (and HOU-DEN doesn’t even cross the mountains), a quick check of the conditions made it obvious we’d made the right decision. Eagle/Vail was gusting to almost 40 knots, and PIREPS (pilot reports, the orange icons below) of turbulence were littered all along what would have been our route, including a somewhat rare PIREP for severe (“aircraft may momentarily be out of control”) turbulence closer to my alternate “skirt-the-mountains” route. But we didn’t need these reports to know it was a meteorologically festive afternoon in the mountains: it was readily apparent from the dustclouds swirling along I-70 and the gusts wobbling our Jeep to and fro. It would have been a miserable small plane flight.
The flying lesson is perhaps obvious, but it’s captured nicely in a one-liner best not forgotten:
It’s better to be on the ground wishing you were in the air, than in the air wishing you were on the ground.
The rest of the weekend was spent admiring the mountains, without a thought about what sort of windy wackiness was going on around them.
Worth the pre-trip weather angst: looking east from the Bighorn Creek Trail toward the Grand Traverse of the Gore Mountain Range, CO.
