Thermals with creeks/rivers

[JonNc]

I’ve read that thermals will go towards the water and then follow direction of water. I have some questions for those experienced with it.

How close to the water do you feel you have to be for your scent to be pulled to water? I hunt some small creeks 6 ft wide and some rivers that are 30-50 ft wide.

As temps heat up, does normal thermal pull (rising thermals) over power the pull from the water?

I found a set up I’m excited about this year and trying to factor all of these things in. Thanks in advance!

[<DK>]

The beast thing you can do is go out there and check to see what its doing. Different conditions may make it do different things.

For creeks I like using them to dump my scent down into them our using the high banks to divert my scent away

[DaveT1963]

BLUF: moving water does NOT cause thermals.

IME, moving water creates vacums and eddies from bank structures and thus MAY influence wind currents.... And often water naturally moves downhill and often towards larger bodies of water which will draw air current downstream as larger bodies heat and cool off slower (if all other factors remain consistent).... So it may, at times be because of thermals... But most of the time it is due to structure of the river/stream surrounding terrain and areas and the vacums created by moving water and not thermals.

Thermals come into play with sunlight and shade... And water will heat and cool off slower then rocky land. north slopes slower that south slopes, etc... IME slower air currents caused by water current can easily be trumped by real thermals. Faster moving water will create far more swirling effects and often overpower true thermals for short stretches. In reality, most streams have more structure and shade then the land immediately adjacent to them, and this is the biggest factor for me when I set up. The one ecxeption is like I noted above if you are close to a large body of water that is affected more by shade/sunlight which can produce a strong thermal. Just my thoughts from hunting them.

[PK_]

Dave nailed it. Flowing creeks and rivers can be fickle. But what you count on is in calm conditions when the thermals drop they will go downhill (usually, save for some uncommon circumstances)and for the most part, the creek/river is obviously at the bottom. So they will go to the water but are not necessarily being drawn BY the water. Many time the thermals will follow the creek/river bed regardless of whether it has water in it or it is dry, because it is just the natural path downhill...

But like Dave said the shade is a big deal. Think of a creek that is shaded out with conifers. That cold water is cooling the air all day long and has some insulation from the canopy. Now like DK said just have to go to those spots in different conditions and see what’s happening.

[muddy]

I have a few areas that have large reservoirs nearby and bigger bluffs/ditches/drainages adjacent. Like posted above calmer days have more predictable thermals. To add onto that I look for days that are going to have bigger temp changes. For example, <10 mph wind in conjunction with a cold frosty morning jumping to 40°+ by noon, then dropping back down that evening. Stacking the deck with prior proper planning can make it seem like you have a huge blower fan purposely pushing your scent in the right direction.

Doing the above killed my buck last fall. Predicted wind wasnt good but I had a calm day with a huge temp fluctuation coming up. I set up on a travel bench with iffy winds. It was maybe 20° but when the sun hit the ground it started warming up fast. Within a hour the wind was blowing perfectly where I needed it because of the creek topography. I never did get a chance to hunt here on an evening hunt but imagine the dropping thermals will be even better, I'll just have to adjust location accordingly for dropping thermals rather than rising.

[Wolfie417]

Hope I'm not hijacking this thread, but I have another water thermal question.
What everyone's experience with thermals relating to huge fast flowing rivers? Say the missouri or Mississippi.
I feel like a giant water source like that could have an even more extreme effect on air currents.

[Lockdown]

Thermals are something I’m not an expert on. In a different thread PK answered a question of mine regarding water that was shaded by cattails. I figured being shallow it would warm up easily, but due to the shade the thick cattails provided, no thermal activity has been seen by myself save one situation.

Tyler and I moved in on some marsh bedding back in my filming days. We were camped out on the buck’s exit trail 30 yards or so from where he hits dry land. We hear sloshing here he comes. It was absolutely dead calm. Just before he hits dry land he stopped. And we never heard another sound. The only thing that makes sense is he barely caught our thermals.

That was the only time I’ve seen thermal activity on shaded water. It was September. PK and RR7 (in the podcast) also mentioned the reason for that is because I’m usually in those areas later in the season when water is colder. Less thermal activity in the first place. makes sense.

Here’s an example and some food for thought. I set up on a food source trying for a doe early October or late September. I had a man made drainage ditch between me and bedding. The wind was super light, but it was there and gently lofting toward bedding. I figured once the sun went down the thermals would kick in and I’d be bullet proof.

Nope I got busted big time. By a fork buck milkweed showed no evidence of thermal activity whatsoever what gives?

On my way home I was obsessing over what happened and why there was ZERO thermal pull. I then realized that the drainage originates at a tile pump 1/2 mile away. Ground water is cold and it didn’t have enough time to warm up in that short of a distance.

Lesson learned.

[DaveT1963]

This is a very simple drawing explanation of setting up and using large water thermals to catch an old cattle country buck doing what mature bucks do. There was a small slough and creek involved but those were not what caused the thermal shift.

I killed him in the very first sit and he did exactly what he should of done..... and so did I in this case (which doesn't happen all that often).

https://youtu.be/4pBGIlX0iv4

[westmichigander]

This is a very simple drawing explanation of setting up and using large water thermals to catch an old cattle country buck doing what mature bucks do. There was a small slough and creek involved but those were not what caused the thermal shift.

I killed him in the very first sit and he did exactly what he should of done..... and so did I in this case (which doesn't happen all that often).

https://youtu.be/4pBGIlX0iv4

Nice video and description.

It seems your thermals were pulling right into where the deer was walking.
If that ditch wasn't there, do you think that buck would have winded you from the thermals before you could have shot him? Or because they had to skirt around that ditch, it allowed your thermals to go down to the lake undetected?

[DaveT1963]

Nice video and description.

It seems your thermals were pulling right into where the deer was walking.
If that ditch wasn't there, do you think that buck would have winded you from the thermals before you could have shot him? Or because they had to skirt around that ditch, it allowed your thermals to go down to the lake undetected?

The buck was shot before he could get my scent in the thermals.... Thats often what it takes is to give him the wind advantage he wants/needs and then setting up just off wind. Had he been able to go another 40 or so yards he would have got my scent

[westmichigander]

Nice video and description.

It seems your thermals were pulling right into where the deer was walking.
If that ditch wasn't there, do you think that buck would have winded you from the thermals before you could have shot him? Or because they had to skirt around that ditch, it allowed your thermals to go down to the lake undetected?

The buck was shot before he could get my scent in the thermals.... Thats often what it takes is to give him the wind advantage he wants/needs and then setting up just off wind. Had he been able to go another 40 or so yards he would have got my scent

That makes sense. So basically the buck was using the thermals to his advantage and that's why he took that route south of the marsh, opposed to wrapping around the tip and coming down that way. Trying to scent check that marsh for doe, etc...

game of inches..

[DaveT1963]

Nice video and description.

It seems your thermals were pulling right into where the deer was walking.
If that ditch wasn't there, do you think that buck would have winded you from the thermals before you could have shot him? Or because they had to skirt around that ditch, it allowed your thermals to go down to the lake undetected?

The buck was shot before he could get my scent in the thermals.... Thats often what it takes is to give him the wind advantage he wants/needs and then setting up just off wind. Had he been able to go another 40 or so yards he would have got my scent

That makes sense. So basically the buck was using the thermals to his advantage and that's why he took that route south of the marsh, opposed to wrapping around the tip and coming down that way. Trying to scent check that marsh for doe, etc...

game of inches..

Exactly

[JonNc]

BLUF: moving water does NOT cause thermals.

IME, moving water creates vacums and eddies from bank structures and thus MAY influence wind currents.... And often water naturally moves downhill and often towards larger bodies of water which will draw air current downstream as larger bodies heat and cool off slower (if all other factors remain consistent).... So it may, at times be because of thermals... But most of the time it is due to structure of the river/stream surrounding terrain and areas and the vacums created by moving water and not thermals.

Thermals come into play with sunlight and shade... And water will heat and cool off slower then rocky land. north slopes slower that south slopes, etc... IME slower air currents caused by water current can easily be trumped by real thermals. Faster moving water will create far more swirling effects and often overpower true thermals for short stretches. In reality, most streams have more structure and shade then the land immediately adjacent to them, and this is the biggest factor for me when I set up. The one ecxeption is like I noted above if you are close to a large body of water that is affected more by shade/sunlight which can produce a strong thermal. Just my thoughts from hunting them.

Great info, that all makes a lot of sense. The best tree I found to hunt this spot would probably put me upwind of a perennial scrape I found, but it is above it uphill and once thermals kick in would put my scent stream well above the deer. For evening, I may have to sit on the ground just below the old logging trail being used by the deer. Good coverage there and great access. What you said basically makes me think I will just play the thermals as usual and not let the water factor too much into the equation. The water I would be close to is probably 30 yards wide and not very deep.

[DaveT1963]

Great info, that all makes a lot of sense. The best tree I found to hunt this spot would probably put me upwind of a perennial scrape I found, but it is above it uphill and once thermals kick in would put my scent stream well above the deer. For evening, I may have to sit on the ground just below the old logging trail being used by the deer. Good coverage there and great access. What you said basically makes me think I will just play the thermals as usual and not let the water factor too much into the equation. The water I would be close to is probably 30 yards wide and not very deep.

I think that depends really as thermals can be finicky on streams.... Always best to be dropping milk weed and adjust on the fly. Where I live the mature bucks will use the evening thermals which often means setting up below the scrape..... And if there is steep banks you msy find the normal day thermals may not be straight up.... Especially if there is a drainage going up the ridge close by or a large open area near the creek. So many variables that really its best to drop the weed and make adjustments. Also I find coming in side hilling is often best, especially if you are pretty sure which way bucks will approach. If I come in from on top, Id come in hopefully using a ditch or dry/wet creek coming down and then side hill..... I'd be dropping weed and Id stop as soon as I noticed the weed stopped following the side creek....