Thermals

[Woods Walker]

MANY things can affect thermals, and each situation is different and there's no set result for any of them.
 
However.....there are two constants that don't change....
 
1. Warm air rises.
 
2. Cold air settles.
 
Generally on a morning hunt, as soon as the sun starts warming the air in and around you, that air will rise. Now, the degree of rise is dependent on many things, the most obvious being terrain, humidity, and the actual wind itself.
 
In a morning stand on a hillside, you can expect the air to RISE up the slope after the sun warms it.
 
Now to complicate this, if you head into your stand in the dark on a damp/humid morning, the scent that you leave on the way in may have a tendency to stay on the ground or even settle until the sun rises. This can work against you if there are deer below you. This factor is also one that suggests that in some cases you may want to wait until the sun starts to rise and warm the air on the slope before you start into the stand. It'll be light enough to see then, and you can slowly stillhunt your way in. I've done this many times, and have even killed a deer several times before I got to my stand.
 
The opposite occurs in the evening, as soon as the air starts to cool. I find that because I haven't smoked for over 45 years, and have a good sense of smell, I can many times smell or "feel" the evening cool air thermals as they begin to slide downslope. If I, with my modern human/part time deer hunter inferior nose and senses can detect this, you'd better believe that a deer can do it in spades!!!
 
A really good way to see this effect, is to get some colored smoke bombs (most fireworks places sell them), and go to your area before the season starts and light some off to see how the thermals work.

[bowhuntingbiker]

I hunt mostly flat ground, but do go to areas with hills. How do you tell where the wind goes? Is there some way to tell how the wind will (may) swirl? I have the wind indicator powder, but how do hills affect the wind and how do you know where to set up?

[Goose]

Other than being there and using the powder, I picture everything like a stream.If there is a rock in the current the current will go around it leaving a swirling pool right behind the rock. Using this has helped me picture the wind a lot better.
Other than that the basics are: In the mornings the thermals bring your scent up and in the evenings the thermals carry your scent down.
Ravines will cause your scent to swirl, so unless you have a strong dominant wind, try to avoid ravines.

Hope this helps.

[bowhuntingbiker]

Thanks Goose. I will give this a try. I don't have enough experience in the hills to know what to do, but I love to hunt there.

[FFKEVIN]

ORIGINAL: Goose

Other than that the basics are: In the mornings the thermals bring your scent down and in the evenings the thermals carry your scent up.

[font="Tahoma"]I always thought that thermal currents generally rise in the morning as the sun heats up the air, and fall in the evening as the air cools.

Am I right or wrong on this???[/font]

[Bowtechian]

ORIGINAL: FFKEVIN

quote]

[font=tahoma]I always thought that thermal currents generally rise in the morning as the sun heats up the air, and fall in the evening as the air cools.

Am I right or wrong on this???[/font]

 
I think you're right. That's the way I've always heard it. 

[Goose]

You guys are correct, I was backwards...Sorry
Ill edit my first post[:)]

[MSHunter]

ORIGINAL: Bowtechian

ORIGINAL: FFKEVIN

quote]

[color="#0000ff"][size="3"][font="tahoma"]I always thought that thermal currents generally rise in the morning as the sun heats up the air, and fall in the evening as the air cools.

Am I right or wrong on this???[/font][/size][/color]

I think you're right. That's the way I've always heard it. 

No, you're right on this. After reading Goose's post last evening, I thought to myself, "this seems 180 out from what I've read before". I spent the rest of the evening researching this.  I'm thinking Goose was just checking to make sure we were awake.

[Goose]

Your right MSHunter......you all passed!   LOL!!

[Woods Walker]

Just remember that warm air rises and cold air sinks. Barring local wind conditions, this will be the case.
 
But there's another wrinkle.......
 
If you are hunting a stand that's on a hillside, and your stand is a "morning" stand, and thus on the uphill side of where you expect game to approach from, when you go to it in the pre-dawn dark your scent will SINK down the hill and/or pool on the ground, especially on a damp or high humidity morning with little or no wind. That means that you may potentially alert deer that will be under or downhill from you, UNTIL THE SUN BEGINS TO WARM THE AIR, and then it will rise.
 
We have a situation like this on one of the farms I hunt. It's a pretty steep hillside that runs N/S. If there's no wind to move the air, you will definately have a situation where the thermals will work BOTH ways on you in the matter of a few hours.
 
What I've done for this, is wait in the dark at the top of the ridge until the sun begins to warm the air, and then stillhunt down to my stand with the thermal air currents in my face.
 
A good technique to employ for thermal "scouting" on your hunting ground, is to get some colored smoke bombs, and light them off different times of the morning or afternoon to actually SEE what they are doing. It's quite educational and sometimes surprising. When it comes to winds and air currents, all is not what it seems many times.
 
I even learned some things one day while scouting on a windy day. I was on a west slope of a N/S running ridge, and there was a pretty good east wind that was blowing hard at the top of the ridge. I was on the protected side of the ridge, and out of the direct wind. I lit a smoke bomb and watched the colored smoke rise up (the thermal) in the still air until it hit the easterly breeze. It then moved pretty quick until it hit an eddy that was quite a ways downhill from me, where it then swirled down and the BACK up the hill at me! Had I been hunting in that spot for deer that were downhill from me, they'd maybe have gotten my scent stream direct, and I'd of never even known it.
 
The smoke bombs will also educate you as to any "sinks" (natural... albeit slight...low areas where your scent "pools"), even though there's a prevailing breeze or thermal.