We've been working somewhere south of Grande Prairie, Alberta. Big flat land, a few hours work and then company tells us where the next job is. We're supposed to fly across the Rocky Mountains from Alberta to British Columbia. There is a lot of disorganized mid level cloud, with sufficient vertical development forecast above our service ceiling that it's not appropriate to take this airplane over the cloud. There will be a high concentration of supercooled water droplets lurking in the clouds, water that has remained liquid despite being cooled below the freezing point. All it needed in order to freeze is a good jolt, like being smacked into the wing or propeller of my airplane, where it could form a deadly coating. So going through the clouds is out. Under the clouds, however, is not out of the question. There is a chance that clouds or intense rainshowers with downdrafts could block the passes, but there are actually quite a few ways through. There are also ridiculous west winds.
I set a westward course and study the charts, as I go, plotting out half a dozen possible routes, with contingency plans and turnback options. I note the GPS coordinates of the key points on each route from the map and enter them in the GPS, helping me to ensure I don't miss a turn. In the mountains it's so easy not to see the point at which you should have taken a different valley, or to think that what is actually a tiny blind canyon is the turn you needed to take. I brief my tech guy, a non-pilot crew member on the plan and adjust course slightly to head for the first planned option, near Grande Cache.
I haven't even properly entered the first valley there, when we encounter moderate turbulence, and I can see that clouds already make it challenging getting through here. I turn around, a no-brainer. Not only are the clouds an issue, but the turbulence which is uncomfortable and tiring for the people may be damaging for our electronic payload. Instead of trying the next option I planned, I abandon everything and head northwest, paralleling the mountain range. I've decided we need more fuel before we continue with what is going to be a long slow trip west with more false starts. I could get to Grande Prairie quite quickly, but with these winds I feel that it will be forever getting back, so I announce we're going to Dawson Creek for fuel. It's a fair ways north and the flight follower even asks why I am going there. I'm tell him it's to avoid coming back against the wind, but really that doesn't add up. I don't know one hundred percent why I chose that fuel stop. The mountains do get lower that way.
We fuelled up, checked the weather with some more sources and successfully made the slow, westward into-wind trek. Turbulence is nil to light and we only have to make a few turns and altitude changes to evade the clouds. While I'm en route flight services broadcasts an urgent SIGMET for severe turbulence. It covers pretty much everywhere I might have crossed south of my eventual route. A SIGMET is an update announcing severe weather that wasn't in the original forecast. I pretend that I used my elite pilot skills to deduce that the west winds would interact with the many folds of the mountains to create turbulence there and not here. But did I? How did I do that? Absent that knowledge, it was a weird decision. Was it luck? Was it some instinct that I acted on without fully communicating to myself?
They say a pilot starts out with two bags: one of luck, which starts out full, and one of experience, which starts out empty. The trick is to fill the experience bag before you run out of luck. But for this trip, I honestly don't know which bag I used.