No Answers For Inversions
May 3, 2011 Perhaps the problem that seems to plague and concern applicators most is inversions. According to Dr. Tom Wolf of Agriculture and Agri-Food Canada, under inversion conditions, turbulence is suppressed because adjacent air layers don’t mix with each other. Any drift in the air remains concentrated and may hang over the treated area for a long time. If wind speed increases, a spray drift cloud moves off the treated area and can cause considerable damage at its destination. The wind at this time is slow and unpredictable.
Wolf points out the irony is inversions are usually associated with dead-calm conditions. A well-meaning applicator trying to avoid wind may inevitably spray at these seemingly ideal times. (Source: Government of Saskatchewan, Ministry of Agriculture)
Gordon Cockrum, crop protection division manager with The McGregor Co., Colfax, WA, says applicators joke that there are two kinds of weather: it’s too windy to spray or there’s an inversion. The wind speed is too high or it’s basically zero. “There’s really no technology that I’m aware of that helps you during inversions … you simply cannot treat,” he says.
Cockrum estimates the conditions occur fully 15% to 20% of the time and are most common at first light and right before sunset.
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