During a short outdoor navigation course yesterday, nature once again enjoyed mocking me a little.
While discussing methods of using the wind to navigate, I had explained how wind direction is surprisingly constant over a period of hours and although small shifts are common, large changes are much less so, and complete reversals very rare. The key is understanding that a significant change in wind direction will be caused by a change in the relationship between your location and a nearby weather system, ie. a front moving through. The change in weather is usually gradual enough to foretell of wind shifts, but not always…
Yesterday we witnessed a complete flip, the wind direction shifted almost 180 degrees from south-southwest to north in one hour. This was something that I had just proclaimed to be almost unheard of, unless there was a complete change in weather. The weather had not yet changed, there remained scattered cumulus clouds, which made me uneasy. I came close to volunteering to eat my hat if we did not witness a quite serious weather change shortly, but resisted and just said that it was very likely.
Fortunately, minutes later the sun disappeared, the scattered cumulus clouds merged into a darkening blanket and the rain began to pour. Even cold rainwater trickling down the back of my neck was a better sensation than feeling that nature has a malevolent disregard for any honest attempt to explain it.
Tags: outdoor navigation course, using the wind to navigate, wind direction
