The Basics of Wind and Thermals and How to Use Them
Want to have more proficient hunts and feel dialed every time you get into a tree? The most bulletproof way to find a big buck in your trap is to master wind and thermals. Even basic knowledge can take your success a long way.
Reading up on thermals can cause frustration. Learning how to use thermals is equally as frustrating. It's time to hone those skills and learn why thermals will make your hunt better.
The Basics
So what are the basics of a thermal? A thermal is air current that moves up or down with changing temperatures. After the sun has risen above the tree line in the morning, the air begins to warm in lower elevations. That warm air then begins to lift. During the evening, the reverse action happens.
Many people have an idea of when these changes will happen. Some say thermals rise at 0930 in the morning and only start falling 45 minutes before last light. But thermals are very dependent on temperature and what the wind is doing.
The basic idea is this, up in the morning, down in the evening. But it's important to test thermals in mixed conditions and terrain to grasp them.
Access
Planning an access route with a thermal current will make your spots more versatile. Maybe the weatherman is calling for a steady wind of more than 7 miles per hour, but when you reach the parking lot, you notice no breeze. You will need a fallback plan B. If you can access from below, you'll have an easier time keeping your scent out of bedding areas. Otherwise, the next best option for thermals is using the same access elevation you suspect deer to be using.
Another way to use thermal access is to sneak along a water source. Cold moving water will often override a significant wind. Thermals will pull downhill with the water and help to keep you hidden.
On the other hand, if you find still water, like a deep lake or pond, there is a good chance that you'll get a rising thermal. This is best used for access when deer are bedding close to the water's edge. The time for a tactic like this is before the body of water cooling. When temps first start to fall below freezing outside, deep water is warmer than air and can cause a rising thermal. Late into the season, the water will likely get cold enough to have the same effect as moving spring water.
Tricky Tactics
In hill country, bed hunters will find a buck bed and picture a deer lying with the wind blowing over its back and a thermal rising to its face. While this is sometimes true, a buck will often prefer the safety of cover over wind and thermal combo.
If a buck changed his bedding every time the wind shifted or changed speed, he would spend most of the day on his feet. It's the same argument that says deer always walk with the wind in their nose. We know that's not true because all deer would live in the same place if it were. Deer do what is best for them.
Wind and thermals move like water in a river. Two things can happen when a log or a rock splits the water current. The first is the current will join together on the downstream side. The connection will create a seam if the water current isn't raging. That area is where fish ambush food as it's caught in the mixing seam.
- Current Seam
A seam is like a long and unbroken ridge. Where wind and thermals meet is like a log in a slow to steady current. It creates a mixing seam and is the perfect place for bucks to use that safety during travel. But more importantly, it's the best way for a buck to scent check does from two directions. If you use trail cameras, you will notice this type of buck movement increase towards the middle to end of October and be full bore during the first week of November.
- Current Eddy
The second thing that can happen in the water is an eddy. An eddy is when water moves in a backward direction. It occurs most often when water levels rise and make the current faster. When water moves past what is blocking it, the pressure causes water to be sucked backward. Fish will wait in an eddy and often face downstream, waiting for baitfish to be sucked into the eddy.
Let's say the top of a ridge's upper half is open fields, cuts, or timber. A strong wind that hits a thick edge will eddy and blow backward before correcting. That will disrupt a downward thermal or make an upward thermal stronger. Sitting where the eddy pulls back can help take your wind away from a deer's nose as it emerges from that edge. It may fool even the smartest buck who believes he is entering a risky zone with the wind in his favor.
Weighing Trial and Error
You can learn a few good ideas about wind and thermals through articles and videos. But you will not walk into the woods and automatically be able to apply them to every situation. Be patient because these things take a while to learn in the field. You will not understand them in one season.
To become proficient:
1. Weigh your access and stand options in every location you hunt.
2. Start by taking an educated guess at what the air current is doing.
3. Have some fun hunting that spot; mark it down as a good learning opportunity if you get it wrong. Next time you use that spot, you will know how to find success.
Lastly, the best advice anyone who understands winds and thermals will give you is: Throw out the windicator powder and fill your pockets with milkweed!
Author: Aaron Hepler, Exodus Blackhats Team Member