Greenspun on ice

To follow up on my last posting about ice, here’s an interesting piece by Philip Greenspun about dealing with light icing over the New York area in a Diamond Star. There’s nothing exciting here, no “ohmygodwe’regoingtodie” moments, just the practical, routine way that small plane pilots handle the light rime icing that can happen in any cloud. Philip made sure he had outs, he used one of them, it worked, and he completed his flight uneventfully: this is the kind of piece new IFR pilots have to read.

Ice in Ottawa

Philip did a good job using layperson’s language in his piece, so I’ll try to do the same here. In general (ignoring local effects like weather around the Great Lakes), there are four bands of weather that can hit Ottawa over the year, stacked from north to south like the layers of a cake. First, there’s the really cold, dry Arctic air furthest north. In the summer, that’s far out of reach; in the winter, it often pushes down into Ottawa giving us cold temperatures (too cold for icing) and good visibility. To the south of that, there’s usually a band of mucky, wet air that hovers just around freezing and causes most of the icing problems for airplanes. In the summer, that air is up around Hudson Bay; it passes through Ottawa in the late fall on its way down to the northeastern US, stays down there for much of the winter (occasionally poking up into Ottawa to annoy us), then passes back up through Ottawa in the early spring on its way back to the Arctic. South of that is the dry, moderate air that gives a nice spring, summer, or fall day. We get that for a lot of the summer in Ottawa, and (I’m guessing) it spends the winter down in Florida, giving nice weather for the snowbirds. Finally, the layer furthest south is the hot, wet air from the Caribbean and Gulf of Mexico. In summer, that air sometimes pokes up into Eastern Ontario bringing thunderstorms and other violent weather, but it seems to spend most of its summer southwest of us, tearing up the U.S. midwest.

So, the point of all this is that (if this winter goes like most) the wet, icy weather will move south soon. Philip may have to deal with it all winter, but we (I hope) will soon have more nice, safe, cold days for flying. Of course, with global warming, we could end up getting more of New England’s winter weather, and then winter flying in Ottawa will be much less pleasant. Keep it nice and cold, please.


About David Megginson

Scholar, tech guy, Canuck, open-source/data/information zealot, urban pedestrian, language geek, tea drinker, pater familias, red tory, amateur musician, private pilot.
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