Don't Let the Thermals Fool You

[Mike Belt]

I needed an ENE wind this morning and got it. I was hunting a narrow bottleneck of timber off the end of a cornfield between bedding areas. The problem was that early on when the wind was light the field was heating up faster than the woods. Heat rises (thus the thermals) and the updraft was faster than the wind was blowing sucking my scent against the wind into the field. It didn't last long and would have tipped off any deer moving there. Watch out for that.

 

[LanceS4803]

I've got an odd "cove" of a field where the mature bucks hang out. It is only an acre off a larger field, but there is a rise at the mouth so you can't easily see into it.
Set up a pop-up blind, but have been busted each time. The wind usually blows from the straight west, but the thermals and trees cause the wind to blow straight south, right into the dead end field and down the ravine in the evenings.
I'm giving up on this spot.

 

[156p&y]

It can also reverse itself in the evening when temperatures start to drop. I've got some places I can only hunt in the morning with a certain wind and some for evenings because of this. Conditions tend to strengthen on clear days because of the radiant heat from the sun. It helps that I study thermal dynamics and thermography for work. I often find myself thinking how does this affect this house but many times I find myself thinking how can I use this in the woods. I think I have a problem! :crazy:


Every once in a while you can find the holy grail of thermals where it sucks your scent straight up in the mornings so nothing will smell you no matter where they come from.

 

[catman529]

If you are 20 ft up and your scent is being carried straight into the thermal then wouldn't it just blow up and away?

 

[BSK]

If you are 20 ft up and your scent is being carried straight into the thermal then wouldn't it just blow up and away?

Not necessarily. Using thermals to draw your scent upwards works many times, but I wouldn't count on it.

 

[BSK]

Every once in a while you can find the holy grail of thermals where it sucks your scent straight up in the mornings so nothing will smell you no matter where they come from.

And that's why I end up hunting north-south oriented ridge-lines so much on clear, calm mornings. The first rays of the sun hit my location first, the air warms and rises, drawing my scent vertically with it. On a clear, calm morning, I can hardly be scented by a deer once the sun peaks over the horizon.

 

[Mike Belt]

catman...Anytime you're sitting in an area that's shaded and cooler than the adjacent area being heated by the sunrise there's a chance the thermal current created by the warmer air rising will create a vacuum at ground level and suck up the surrounding air with it. This includes your scent even if the wind is blowing the opposite direction. Once wind speed increases to over 2-3 mph this effect is usually negated. That's why I much prefer to hunt on days with a steady 5-10 mph wind.

 

[156p&y]

I do basically the same thing Mike. I've got one spot that creates an awesome thermal in the mornings. The sun hits it perfect, its oriented perfect, and the pitch of the ridge is perfect. I have seen some huge deer there but have yet to score on one, all of which were traveling with the wind blowing across the front of their face.