Hunting the Falling Thermal

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Re: Hunting the Falling Thermal

Unread postby dagger » Tue Oct 09, 2018 11:51 am

This here thermal conversation is exactly what I've been talking about with my hunting friends for awhile. Main wind direction is important but understanding what the thermals are going to do is even more important.

There's been many a time sitting in the woods, maybe 30-50 yards from a swamp edge and the wind can be in my face all night, then the sun goes behind the trees and it'll totally reverse direction pulling all your scent into the swamp.

I've also seen on a big ridge, the rising thermals overpower a pretty stiff wind.

Very good discussion going on here guys, keep it coming.


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Re: Hunting the Falling Thermal

Unread postby Evanszach7 » Tue Oct 09, 2018 11:56 am

headgear wrote:
Divergent wrote:
headgear wrote:You start to find some of the better bedding areas all have a thermal working in their favor, it is something I focus on when scouting.


How do you find them using the thermals in those situations? And, what kind of topography?


I hunt mostly swamps so take that into consideration. Lets say I have a huge swamp transition that I can scout for a couple of miles and I see a bunch of small points, some islands and too many to count lone trees that could all work for bedding. Now you have to walk the entire transition anyway to cover all of this stuff so I am scouting the whole thing. However if there are 8-10 spots I am really keying in on and a couple of those have a nice ridge or V shaped valley nearby the bedding seems to be closer to those thermal areas because the bucks can stage up after dark and smell what is up on top of the hill or smell both sides of a valley as the thermals fall down into the swamp. Or on flatter land there might be a pond, lake or beaver dam out in the swamp that will have a thermal pull so they might prefer that area over a spot a half mile away that might look better but doens't have as good of thermals.

Edit: Sometimes these thermal terrain features can also cause some swirling winds too so another reason they seem to like them.


I see the same kind of bedding with switchgrass and briar type crp, especially before it begins to lay down with the frost and it’s still 4-6 ft high- Ky (September-October) & Ohio (October). The stuff is similar to cattails where they can’t see out. The height of it laying down with frost coincides with 50% of the leaves having dropped and I’ll see them shift to hill country style bedding.

They’re typically bedding with a wind advantage. Mature bucks more so on the fringes, wind to back of typical human access with wind blowing into the crp, and non dominant bucks and does more so scattered within. Either way, most bucks will favor staging within the crp or working to the edge that has a low dropping thermal (valley or farm country style low point). I’ve been busted by setting up with an off wind for the fringe and blowing the deer out in the Crp. Biggest surprise so far this year was wind bumping a mature buck and solid 2.5 year old passing a crp field like this on my way to hunt a fresh scrape during steady rain. Still weird to me they’d be bedding there during rain with no cover.

I’ve been observing 4 crp fields this year and it’s a pretty common bedding strategy. And various ones over the past few years. The tough part has been abandoning the stand and a sight advantage to going in for a ground setup. Lots of pressure around the crp edges, driven by lots of annual rubs since does tend to bed in these year round. Makes it hard to pattern exit trails, or keep bucks bedding in these areas. Ground hunting is tough with most sight lines being 15 yards.

With all that said... I’m seeing them use wind for bedding, not so much rising thermals, even though the topo of a few could favor that. And, it’s pretty common for falling evening thermals to be used for staging.
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Re: Hunting the Falling Thermal

Unread postby Chuck B » Tue Oct 09, 2018 1:11 pm

This is a great thread. Thermals are definitely underrated in terms of importance. I am starting to really figure them out where I usually hunt, but still have lots to learn. I have a few different spots that are just dynamite (deer moving through them every evening), but I get busted so often due to thermals. I am beginning to think that I have no chance of hunting these deer in these spots because I just can’t beat the thermals. But, I am not going to quit those spots yet tho, there has got to be a way...
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Re: Hunting the Falling Thermal

Unread postby Twenty Up » Tue Oct 09, 2018 2:35 pm

I hunted a bed this past Friday and as my thermals should’ve been falling, maybe 15 minutes before dark a group of does came feeding up the creek bottom behind me. Down wind and below me. None stopped or changed behavior. So I dropped some milkweed only to have it hover in front of me for 10-15 seconds before slowly falling straight down.

Interested to see if anyone else has ever had similar experiences as mine.
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Re: Hunting the Falling Thermal

Unread postby Divergent » Tue Oct 09, 2018 5:04 pm

Evanszach7 wrote:
headgear wrote:
Divergent wrote:
headgear wrote:You start to find some of the better bedding areas all have a thermal working in their favor, it is something I focus on when scouting.


How do you find them using the thermals in those situations? And, what kind of topography?


I hunt mostly swamps so take that into consideration. Lets say I have a huge swamp transition that I can scout for a couple of miles and I see a bunch of small points, some islands and too many to count lone trees that could all work for bedding. Now you have to walk the entire transition anyway to cover all of this stuff so I am scouting the whole thing. However if there are 8-10 spots I am really keying in on and a couple of those have a nice ridge or V shaped valley nearby the bedding seems to be closer to those thermal areas because the bucks can stage up after dark and smell what is up on top of the hill or smell both sides of a valley as the thermals fall down into the swamp. Or on flatter land there might be a pond, lake or beaver dam out in the swamp that will have a thermal pull so they might prefer that area over a spot a half mile away that might look better but doens't have as good of thermals.

Edit: Sometimes these thermal terrain features can also cause some swirling winds too so another reason they seem to like them.


I see the same kind of bedding with switchgrass and briar type crp, especially before it begins to lay down with the frost and it’s still 4-6 ft high- Ky (September-October) & Ohio (October). The stuff is similar to cattails where they can’t see out. The height of it laying down with frost coincides with 50% of the leaves having dropped and I’ll see them shift to hill country style bedding.

They’re typically bedding with a wind advantage. Mature bucks more so on the fringes, wind to back of typical human access with wind blowing into the crp, and non dominant bucks and does more so scattered within. Either way, most bucks will favor staging within the crp or working to the edge that has a low dropping thermal (valley or farm country style low point). I’ve been busted by setting up with an off wind for the fringe and blowing the deer out in the Crp. Biggest surprise so far this year was wind bumping a mature buck and solid 2.5 year old passing a crp field like this on my way to hunt a fresh scrape during steady rain. Still weird to me they’d be bedding there during rain with no cover.

I’ve been observing 4 crp fields this year and it’s a pretty common bedding strategy. And various ones over the past few years. The tough part has been abandoning the stand and a sight advantage to going in for a ground setup. Lots of pressure around the crp edges, driven by lots of annual rubs since does tend to bed in these year round. Makes it hard to pattern exit trails, or keep bucks bedding in these areas. Ground hunting is tough with most sight lines being 15 yards.

With all that said... I’m seeing them use wind for bedding, not so much rising thermals, even though the topo of a few could favor that. And, it’s pretty common for falling evening thermals to be used for staging.


They typically use wind specific bedding from my experiences. I hunt hill country, so i'm not sure if this changes due to topography. How are you setting up with your ground game?
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Re: Hunting the Falling Thermal

Unread postby Divergent » Tue Oct 09, 2018 5:07 pm

Chuck B wrote:This is a great thread. Thermals are definitely underrated in terms of importance. I am starting to really figure them out where I usually hunt, but still have lots to learn. I have a few different spots that are just dynamite (deer moving through them every evening), but I get busted so often due to thermals. I am beginning to think that I have no chance of hunting these deer in these spots because I just can’t beat the thermals. But, I am not going to quit those spots yet tho, there has got to be a way...


I'd be interested to see how it sets up. I find the lower I can get in the late evening, the more i can get away with related to falling thermals. Of course, I have to keep in mind how far from I am from cover and what is the driving force behind the deers travel pattern.
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Re: Hunting the Falling Thermal

Unread postby Divergent » Tue Oct 09, 2018 5:35 pm

Twenty Up wrote:I hunted a bed this past Friday and as my thermals should’ve been falling, maybe 15 minutes before dark a group of does came feeding up the creek bottom behind me. Down wind and below me. None stopped or changed behavior. So I dropped some milkweed only to have it hover in front of me for 10-15 seconds before slowly falling straight down.

Interested to see if anyone else has ever had similar experiences as mine.


It sounds like the change hadn't fully occurred yet, since the milkweed was balanced. There's so many different factors that can effect the thermal pull.
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Re: Hunting the Falling Thermal

Unread postby Divergent » Tue Oct 09, 2018 5:46 pm

There are a few things that effect thermals that I haven't mentioned. Cloud cover can make the thermals get squirrelly if the wind speed is low enough. A passing cloud can cool an area just long enough to see the thermals balance out or fall, depending on the time of day. I find that a dense tree canopy can effect the thermals as well. You can find huge differences in just a few yards when you have field edges or select cut timber butting up to mature timber. I was hunting an area just last week on an out-of-state hunt in Georgia. It was a large field with a select cut, pine transition, that butted up against a dense mature canopy. If i was standing inside the dense canopy, my thermals were pulling South, down the draw into a bottom because the ground was cooler. If i was hunting in the select cut transition, I had no falling thermal advantage because the ground was still receiving some sun, so there was a slight thermal rise. This caused the "wind" to blow straight to the East and into the bedding area/exit trail. In the field on top, the "wind" was coming out of the south...which was a complete 180* change from inside the dense canopy that was shaded from the sun. If i were to setup outside of the dense canopy, i would've been busted if a deer came down the trail.

Cold creeks can have an effect on thermals too. I have areas that i can hunt in the middle of the day and have a falling thermal. These cold creeks seem to cool the surrounding air and there's a small pocket surrounding the creek that will have this falling thermal. Just 20 yards up the hill will have a rising thermal. You might also find that a particular side of the creek has more shade throughout the day or certain times of the day. Your thermals will change in these locations due to the ground cooling.
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Re: Hunting the Falling Thermal

Unread postby Divergent » Tue Oct 09, 2018 5:55 pm

Tufrthnails wrote:It finally made sense to me on a Coyote hunt in Jan in KY. Temp was 9f that morning. Me and the cousin knew where a family pack was holed up. Snuck in down wind of them. wind in our face coming out of the north, but only 3-4mph and not steady. First yote came out to the call about 300 yards NNW. It came into around 150 yard hugging a transition line of a drainage with trees along it only maybe 20ft wide. Just as he got to the NW of us he froze. Yipped and hauled but back in to the woods. We were baffled as he never looked at us he was looking at the call in the brush across from us the whole time.

So the AH HA moment was....Tony fired up a cig, since we were busted. the smoke ran down to the ground and directly down the drainage. It was amazing to watch if smoke fall and crawl on the ground.


That's a cool story. Just one of the reasons I prefer hunting in a ditch now. Just like the ditch carried your scene to the note...I will setup in a way that my scent is carried away from expected travel.
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Re: Hunting the Falling Thermal

Unread postby Divergent » Tue Oct 09, 2018 6:05 pm

justdirtyfun wrote:I'm just talking out loud with this conversation.
On a point bed , a deer gets scent from below with rising thermals all day. At this point he assumes the coast is clear. During his rise and stage when the sun sets he often will walk downhill. Wind to back and watching in front. Which I consider normal behavior since feeding in open is also done wind to back and watching in front.

This same deer will blow like crazy if he spots you since you weren't supposed to be there. He had scented that area with thermals all day. Right?

This is the opportunity that is often talked about for falling thermals. Understanding gives us a chance to exploit the false sense of security.


Yes, i've seen it time and time again. I've got a couple of thoughts on this myself, but I haven't come to a conclusion just yet. I'm not sure if the rising thermals distribute your scent over such a broad area or if a bedded deer just tolerates more scent vs a deer on their feet.
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Re: Hunting the Falling Thermal

Unread postby Divergent » Tue Oct 09, 2018 6:07 pm

dagger wrote:This here thermal conversation is exactly what I've been talking about with my hunting friends for awhile. Main wind direction is important but understanding what the thermals are going to do is even more important.

There's been many a time sitting in the woods, maybe 30-50 yards from a swamp edge and the wind can be in my face all night, then the sun goes behind the trees and it'll totally reverse direction pulling all your scent into the swamp.

I've also seen on a big ridge, the rising thermals overpower a pretty stiff wind.

Very good discussion going on here guys, keep it coming.


Yeah, some of those bigger hills can really generate some thermal pull.
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Re: Hunting the Falling Thermal

Unread postby Evanszach7 » Tue Oct 09, 2018 9:05 pm

Divergent wrote:
Evanszach7 wrote:
headgear wrote:
Divergent wrote:
headgear wrote:You start to find some of the better bedding areas all have a thermal working in their favor, it is something I focus on when scouting.


How do you find them using the thermals in those situations? And, what kind of topography?


I hunt mostly swamps so take that into consideration. Lets say I have a huge swamp transition that I can scout for a couple of miles and I see a bunch of small points, some islands and too many to count lone trees that could all work for bedding. Now you have to walk the entire transition anyway to cover all of this stuff so I am scouting the whole thing. However if there are 8-10 spots I am really keying in on and a couple of those have a nice ridge or V shaped valley nearby the bedding seems to be closer to those thermal areas because the bucks can stage up after dark and smell what is up on top of the hill or smell both sides of a valley as the thermals fall down into the swamp. Or on flatter land there might be a pond, lake or beaver dam out in the swamp that will have a thermal pull so they might prefer that area over a spot a half mile away that might look better but doens't have as good of thermals.

Edit: Sometimes these thermal terrain features can also cause some swirling winds too so another reason they seem to like them.


I see the same kind of bedding with switchgrass and briar type crp, especially before it begins to lay down with the frost and it’s still 4-6 ft high- Ky (September-October) & Ohio (October). The stuff is similar to cattails where they can’t see out. The height of it laying down with frost coincides with 50% of the leaves having dropped and I’ll see them shift to hill country style bedding.

They’re typically bedding with a wind advantage. Mature bucks more so on the fringes, wind to back of typical human access with wind blowing into the crp, and non dominant bucks and does more so scattered within. Either way, most bucks will favor staging within the crp or working to the edge that has a low dropping thermal (valley or farm country style low point). I’ve been busted by setting up with an off wind for the fringe and blowing the deer out in the Crp. Biggest surprise so far this year was wind bumping a mature buck and solid 2.5 year old passing a crp field like this on my way to hunt a fresh scrape during steady rain. Still weird to me they’d be bedding there during rain with no cover.

I’ve been observing 4 crp fields this year and it’s a pretty common bedding strategy. And various ones over the past few years. The tough part has been abandoning the stand and a sight advantage to going in for a ground setup. Lots of pressure around the crp edges, driven by lots of annual rubs since does tend to bed in these year round. Makes it hard to pattern exit trails, or keep bucks bedding in these areas. Ground hunting is tough with most sight lines being 15 yards.

With all that said... I’m seeing them use wind for bedding, not so much rising thermals, even though the topo of a few could favor that. And, it’s pretty common for falling evening thermals to be used for staging.


They typically use wind specific bedding from my experiences. I hunt hill country, so i'm not sure if this changes due to topography. How are you setting up with your ground game?


Still trying to figure out the ground game on these setups. Tried at the closest red 40 yards into the crp with trails coming to it, and a small scattered 7-8’ pine area on the edge. Both sets are tough with does coming from the timber passing near both into the Crp. Found a 2 stick tree on the last hunt where I’ll be overlooking a 6-7’ briar section of the crp on an inside corner within 20-40 yards of beds. Waiting on a NE wind for that one-risky set.
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Re: Hunting the Falling Thermal

Unread postby Evanszach7 » Tue Oct 09, 2018 9:10 pm

Divergent wrote:
Evanszach7 wrote:
headgear wrote:
Divergent wrote:
headgear wrote:You start to find some of the better bedding areas all have a thermal working in their favor, it is something I focus on when scouting.


How do you find them using the thermals in those situations? And, what kind of topography?


I hunt mostly swamps so take that into consideration. Lets say I have a huge swamp transition that I can scout for a couple of miles and I see a bunch of small points, some islands and too many to count lone trees that could all work for bedding. Now you have to walk the entire transition anyway to cover all of this stuff so I am scouting the whole thing. However if there are 8-10 spots I am really keying in on and a couple of those have a nice ridge or V shaped valley nearby the bedding seems to be closer to those thermal areas because the bucks can stage up after dark and smell what is up on top of the hill or smell both sides of a valley as the thermals fall down into the swamp. Or on flatter land there might be a pond, lake or beaver dam out in the swamp that will have a thermal pull so they might prefer that area over a spot a half mile away that might look better but doens't have as good of thermals.

Edit: Sometimes these thermal terrain features can also cause some swirling winds too so another reason they seem to like them.


I see the same kind of bedding with switchgrass and briar type crp, especially before it begins to lay down with the frost and it’s still 4-6 ft high- Ky (September-October) & Ohio (October). The stuff is similar to cattails where they can’t see out. The height of it laying down with frost coincides with 50% of the leaves having dropped and I’ll see them shift to hill country style bedding.

They’re typically bedding with a wind advantage. Mature bucks more so on the fringes, wind to back of typical human access with wind blowing into the crp, and non dominant bucks and does more so scattered within. Either way, most bucks will favor staging within the crp or working to the edge that has a low dropping thermal (valley or farm country style low point). I’ve been busted by setting up with an off wind for the fringe and blowing the deer out in the Crp. Biggest surprise so far this year was wind bumping a mature buck and solid 2.5 year old passing a crp field like this on my way to hunt a fresh scrape during steady rain. Still weird to me they’d be bedding there during rain with no cover.

I’ve been observing 4 crp fields this year and it’s a pretty common bedding strategy. And various ones over the past few years. The tough part has been abandoning the stand and a sight advantage to going in for a ground setup. Lots of pressure around the crp edges, driven by lots of annual rubs since does tend to bed in these year round. Makes it hard to pattern exit trails, or keep bucks bedding in these areas. Ground hunting is tough with most sight lines being 15 yards.

With all that said... I’m seeing them use wind for bedding, not so much rising thermals, even though the topo of a few could favor that. And, it’s pretty common for falling evening thermals to be used for staging.


Gotta bite my tongue on this one too... just thought of an example for a bowl on a separate thread from earlier this season:

Surprised myself early season in Ky when I sent my buddy to hunt a bed on a bowl edge with a NE wind. If the bowl were a clock, with noon being the top center, I expected the buck to be at the 10 bed. He ended up being at 2. Due to thick cover 25 yards above him, no wind over the back from the top. He was facing up hill towards noon, and a thick crp field, catching the swirl from 6, so setup to bed a SW swirl on a NE wind day. Between wind gusts he’d have rising thermals. Exit trail from that bed led to oaks below towards the 5. You’d need to setup below the 5 just before the thermal switch and enter from below.

Thought I had the bedding/wind figured out there until he busted the buck and picked up the exit trail. Buck didn’t blow out, but walked off which helped.

Biggest takeaway for me here was the mature buck was counting on thermals and using a wind that paired with those thermals and a 5-6mph sunny wind day. Still wind/thermals to back, but facing up hill to a crp transition line.

They typically use wind specific bedding from my experiences. I hunt hill country, so i'm not sure if this changes due to topography. How are you setting up with your ground game?
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Re: Hunting the Falling Thermal

Unread postby Ahawk116 » Tue Oct 09, 2018 11:55 pm

I got a thermal education last Sunday. I was hunting a bed that is on the point of a creek where the creek makes a U shape. The buck is bedded there on north or north east winds, we had that last Sunday so I went in for the kill. On the paddle in I got excited because my thermals were blowing straight down the creek following the water. Pulled up to the tree I was going to sit and got settled in the tree. A half hour later one of the magnetic closures on my pack slapped shut and the buck got out of his bed and ran off. Much to my surprise he was bedded on the other side of the creek only 30 yards from me. His bedding made absolutely no sense with the wind direction that was called for, but because the wind was only blowing 3-4 mph that day he wasn’t in his worn to the dirt bed, but on the other side of the creek where I assume he can catch the thermal currents from the creek in his bed.

The education is this. When the wind is barely blowing (almost the entire early season in my area) a lot of the bucks are bedded based on thermals.
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Re: Hunting the Falling Thermal

Unread postby headgear » Wed Oct 10, 2018 12:44 am

Divergent wrote:
That makes perfect sense and I actually see the same thing when it comes to fields on top of ridges. The deer gravitate to low spots in fields because of the falling thermal advantage in the evening.


Exactly, anytime they can smell what is up ahead of them they will do it, a lot of the staging areas I hunt have a thermal effect so I am alwasy planning my sets for wind and thermals. Sometimes that puts me in not perfect hunting situations but it has to be done that way or they will bust you. It could be similar in hill country where a buck drops off a point down low so they can smell everything up on top of the ridge, they just love those thermal mixing zones or thermal hubs because everything they can sniff a large area. I even see them in overlooks spots next to the road or parking, there will often be a thermal there that they stage into, it doesn't take a lot of elevation to create one so they can come info play just about anywhere.

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