Quick question on thermals

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Cchez
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Quick question on thermals

Unread postby Cchez » Mon Sep 21, 2020 3:27 am

So last night I had a steady SSE all afternoon into the evening. The milkweed drifted along with the breeze as it should have. Once it calmed down and the thermals kicked in, it was totally opposite. The milkweed was getting sucked back to the SE.

So my question is, do thermals always follow the contours of the land, even when the land is relatively flat? In the picture you can see that the land does slightly slope (my setup is roughly where the red circle is), but it's very very gradual, and feels pretty much flat when you're in there.
Thanks
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Re: Quick question on thermals

Unread postby Huntress13 » Mon Sep 21, 2020 3:51 am

I've heard it said that it is like water flowing, so even if there is a little elevation that is how it goes.
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headgear
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Re: Quick question on thermals

Unread postby headgear » Mon Sep 21, 2020 6:37 am

The thermals are extremely consistent and the bucks use them to their advantage, you have to plan for wind and thermals or you will get busted.
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Re: Quick question on thermals

Unread postby Cchez » Tue Sep 22, 2020 1:36 am

headgear wrote:The thermals are extremely consistent and the bucks use them to their advantage, you have to plan for wind and thermals or you will get busted.


I understand that. But my question was do the thermals always follow the contours of the land downward even when its a very gradually decline?
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Re: Quick question on thermals

Unread postby hcooper84 » Tue Sep 22, 2020 2:08 am

Huntress13 wrote:I've heard it said that it is like water flowing, so even if there is a little elevation that is how it goes.


Huntress is right, as long as the prevailing wind isn't strong enough to over power the thermals; then the cooling air will drop and follow the path of least resistance, 99% of the time down.
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Re: Quick question on thermals

Unread postby <DK> » Tue Sep 22, 2020 2:36 am

Cchez wrote:
headgear wrote:The thermals are extremely consistent and the bucks use them to their advantage, you have to plan for wind and thermals or you will get busted.


I understand that. But my question was do the thermals always follow the contours of the land downward even when its a very gradually decline?


Yes.

The sun is no longer out to 'pull' it and the wind generally comes/goes with the sun. Warm rises/Cool drops. So at prime time yes - your milkweed should drop straight down from your stand or down hill and follow terrain. So when the wind is steady like your hunt, it overpowers the thermals. When the wind stopped and sun went down, the thermals where then in control.

For an example hunting hills - I like to setup on the upper 1/3 of a ditch splitting two ridges. With a Sunny, 7mph, variable N wind - my scent blows down into the ditch, pools up or tumbles around. Once prime time hits, my thermals will still drop down into the ditch. Depending on what elevation I setup on in the ditch - determines how I will see the rising thermal pull/currents in between the wind blowing. With a higher mph wind I will see less rising thermals.

A lot can depend on how open or thick the terrain is. Hills vs flatland. Thick transition lines are very, very key. Another factor can be dominant winds and wind speeds for the day. In flat land - with the right sun/weather conditions you can get a great rising thermal in the mornings where it goes straight up. Those are special spots..

Clear as med, eh? Just keep playing with it and things will work out great for you.
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Re: Quick question on thermals

Unread postby Cchez » Tue Sep 22, 2020 3:05 am

<DK> wrote:
Cchez wrote:
headgear wrote:The thermals are extremely consistent and the bucks use them to their advantage, you have to plan for wind and thermals or you will get busted.


I understand that. But my question was do the thermals always follow the contours of the land downward even when its a very gradually decline?


Yes.

The sun is no longer out to 'pull' it and the wind generally comes/goes with the sun. Warm rises/Cool drops. So at prime time yes - your milkweed should drop straight down from your stand or down hill and follow terrain. So when the wind is steady like your hunt, it overpowers the thermals. When the wind stopped and sun went down, the thermals where then in control.

For an example hunting hills - I like to setup on the upper 1/3 of a ditch splitting two ridges. With a Sunny, 7mph, variable N wind - my scent blows down into the ditch, pools up or tumbles around. Once prime time hits, my thermals will still drop down into the ditch. Depending on what elevation I setup on in the ditch - determines how I will see the rising thermal pull/currents in between the wind blowing. With a higher mph wind I will see less rising thermals.

A lot can depend on how open or thick the terrain is. Hills vs flatland. Thick transition lines are very, very key. Another factor can be dominant winds and wind speeds for the day. In flat land - with the right sun/weather conditions you can get a great rising thermal in the mornings where it goes straight up. Those are special spots..

Clear as med, eh? Just keep playing with it and things will work out great for you.


Thanks. Makes more sense now. I just always thought it had to be a little more of a defined slope in the terrain for it to apply. Lesson learned.
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Re: Quick question on thermals

Unread postby headgear » Tue Sep 22, 2020 3:15 am

Cchez wrote:
headgear wrote:The thermals are extremely consistent and the bucks use them to their advantage, you have to plan for wind and thermals or you will get busted.


I understand that. But my question was do the thermals always follow the contours of the land downward even when its a very gradually decline?


Absolutely yes, they will follow the low ground, so in your photo all the thermals would funnel down to the creek bottom and then flow to the east in the same direction as the water. Any wind and you don't have to worry about thermals but so often that wind dies down at prime time during that last 1/2 hour to hour and that is when the bucks are likely to move. These hills look plenty steep but the thermals are active on gradual and flat land too. Water thermals will also suck in scent from all directions if they can but that is for standing water like a lake or pond.
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Re: Quick question on thermals

Unread postby Colingraat » Mon Sep 28, 2020 4:42 am

I have also heard the illustration of the thermals being like water flowing. I believe I heard it on a podcast from Dan where he made the point of saying that bucks will often enter the field in the lowest point. As the thermals drop at night they pool in the lowest point. Sure enough i was out the next night doing some summer scouting and sure enough this was to be true...and i am in an area which is basically flat.


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