Thermal rise observation over an open exposed area.

[Johnboy]

This past early bow season I was able to sit in my stand bout 20-25ft up and see thermals work in my favor .It was during a steady but light west wind blowing into the food plot planted in turnips and sugar beets. It was an evening hunt, not a lot of time to hunt , and limited to this one stand due to ease of location. My thoughts were no way I'd see deer in the field at all due to west wind.Deer movement also was not great due to 75-80 degree days. I checked wind with milkweed, still west.
Deer(all does)started coming into the field bout 1 hour or so before dark and out of range at 80yds with a bow. I could not figure why they were not smelling me until I watched the milkweed drift slowly towards the deer, slowly sinking at first then at 50yds or so start rising(chimney effect)straight up above the deers' backs in the middle of field. I never got a shot and never got busted. My thought was turnip leaf cover heated up all day exposed to the sun and then those thermals were still rising in the evening until after shooting light due to the daily highs we were having was my conclusion. I never got to test my theory at that stand again or any other open field but was wondering how many of you guys have seen it happen over food plots, open fields, marshes, swamps exposed to sunlight all day. There has to be a time right at or just a little past dark that the thermals would start sinking over open spaces.

[dan]

Dark and/or open soil has a lot more thermal effect than shaded areas with trees... I read up on this a while back and I know somewhere posted deep we talked about it... People who hang glide talk a lot about thermals and wind currents and you can learn a lot studying there forums on the subject... One thing you can look for is birds like vultures circling in the rising thermals. This will show you where the current is rising in flat land.

[stash59]

I would think that just like when you suddenly hit a cooler pocket of air. When walking in low, open, flat dry marsh areas. There would have to be an opposite thing going on in another spot close by. The old physics rule of 'for every action, there's an equal reaction' should apply.

Even at night in cold weather. The pressure from the downward thermals have to get released somewhere. Even if it means traveling down a river bottom clear out to the ocean and then south over the ocean. Just like the water it's following.

Micro weather systems are taking place. In reaction to the terrain, vegetation and heat of the day. Which means small high and low pressure areas exist.

A common weather occurance in the mountains is an air inversion. At times in the winter warmer air gets trapped in the valleys under colder air aloft. Usually caused from a quick traveling cold front pushing over the mountains. That can't move the warmer air out ahead of it. The pressure from the warm air is too great and keeps the colder air above it. You can tell when there's an inversion because all the smoke from wood fires stays down in the valley like a thin fog. When it gets bad people with lung problems are told to stay inside and in larger cities wood fires are often banned.

I'm no expert on all of this. Until I found the Beast I never put all of this together with how it all related to hunting a buck. Common sense with all of this aquired knowledge is where my thinking comes from. If I'm wrong I'm interested in what's actually happening. It's all pretty cool!