The Minuteman’s Guide to Thermal Camouflage

Warfare, be it foreign or domestic, is changing. The modern battlefield is saturated with sensors of all types from drones to night vision to electronic warfare. As this technology becomes more and more available/affordable to civilians, even irregular warfare is evolving. In order to survive the ever-changing nature of war, we must adapt along with it.

Particularly impactful is the common availability of thermal optics. Thermal optics, which read heat signatures, are incredibly potent tools. Although somewhat cost-prohibitive, they are no longer as unobtainable as they once were and can be had for under $2000 in some cases. It is safe to assume that any large-scale civil conflict will see at least some use of thermal optics on both sides, so we must be prepared for this reality.

In order to learn how to deal with a thermal-equipped enemy, we must first understand the technology we are dealing with.

What thermal sensors can do

Thermal optics read differences in temperature within a given field of view and convert that information into a visible color image with different colors representing different levels of heat. The most common palette is “White Hot,” which shows hotter surfaces as white with everything else in a scale of grey to black.

This ability to read purely heat energy allows thermal optics to see things that the naked eye or night vision optics would miss. Thermal optics can:

-See through smoke/fog
-Detect clothes that have absorbed body heat (most clothing)
-Identify vehicles that have been driven recently
-In some circumstances such as snow, see recent footprints
-Detect moving people very easily
-Work both day and night

One more point I should add here is that it is fairly simple to hide from someone on the ground equipped with thermals. Hiding from airborne thermals in small drones and aircraft, however, is a bit trickier because you are forced to think in 3 dimensions for your camouflage.

What thermal sensors cannot do

Thermal optics are not the “eye of Sauron” as some have put it. They have limitations just like any other piece of equipment. Some limitations include:

-They cannot see through glass.
-They cannot see through solid objects such as leaves and branches.
-Battery life is incredibly short, making constant observation very difficult without a large power source.
-Most handheld/drone mounted units are limited to 200-300m detection range for man-sized heat signatures. There are exceptions, but this is true for the majority of sub-$4k thermal optics on the civilian market. State or state-backed actors have access to more powerful units with greater detection ranges, especially when mounted on vehicles.
-A human must observe the image and determine what he is seeing. Humans are fallible, and human nature can be exploited.

How to hide from thermal on the move

At the time of this writing, there is no thermal-defeating uniform or poncho that you can buy. The one company that makes a wearable poncho that effectively masks thermal signature does not sell to civilians.

That said, there are still some effective low-tech ways to conceal yourself from a thermal-equipped enemy. It is important to remember that people are not the only things that generate heat. Rocks, moist ground, and roads retain heat from sunlight for several hours after dark. Recently operated vehicles, certain buildings, and wild animals also read as “hot” to thermal sensors. Also remember that behind the thermal optic there is a human trying to find you. You don’t need to completely block your heat signature, you just need to make yourself indistinguishable from any other random heat signature in the area to fool that human behind the sensor.

Thermal optics cannot see through leaves and branches. So planning a patrol to take you under dense tree cover whenever possible is a good idea to evade airborne sensors. Areas of dense brush accomplish the same thing against ground sensors. If the foliage is thick you could be completely hidden. If it’s not, it may still mask your shape enough to obscure you from an enemy observer. Natural vegetation and jute on a ghillie suit/ ghillie blanket/ cobra hood also does not absorb body heat, and will remain the same temperature as your environment. Applying enough of it in the right places makes your signature as a human unrecognizable, both to visible and thermal optics. So veg up.

The biggest giveaway of a human through thermals is our shape. It is very easy to PID a human that is standing or walking through thermals, even from a distance. However, doing something as simple as crouching or bending over to make your shape more ambiguous can do a lot when you’re being viewed from a distance.

There are certain times in the day when thermal observation is more difficult. One such time is during a phenomenon called “thermal crossover.” Thermal crossover is when the temperature of the terrain drastically shifts twice a day around sunrise and sunset. The average temperature of human skin is 91 degrees Fahrenheit, so if the temperature is higher than that during the day there will come a time when the terrain is about the same temperature as your skin. This makes it much more difficult to detect you, so you should plan your movement during this time if at all possible. Thermal crossover normally lasts roughly 30 minutes before and after sunrise and sunset, depending on your environment. You can estimate the actual time by watching for when the temperature gets close to 91 degrees.

Thermal crossover may not work in cooler climates/seasons for obvious reasons. All is not lost, however. In cooler climates we tend to wear more layers of clothing. The more layers you wear, the colder your heat signature is because less heat is escaping your body.

Some forests also tend to retain heat for hours into the night due to the insulating effect of the canopy. This means that in a forest, apart from thermal crossover, the best time to make movement is the early hours of the night while the ground still reads hot. How long this lasts depends on your environment, but I’ve seen it last until 0300 in some cases. Go out into your environment with your own thermals to get an idea of how long heat is retained.

Hiding from thermals while stationary

Hiding from thermals while stationary is significantly easier. However, there are still some precautions that you should take. If you are paying attention to events in Ukraine right now, you likely have seen a ton of drone footage of artillery strikes or air strikes on static positions. Another common trend is both sides dropping munitions on each other from the drones themselves. This is what happens when a static position (foxhole, LP/OP, patrol base, etc.) is not camouflaged from the air. The Ukrainians seem to be especially bad at this, making large and obvious trench lines that are impossible to miss from above.

The moral of the story is this. On the modern battlefield, to be detected is to be targeted, and to be targeted is to be killed. This applies to potential civil conflict as well. During some force-on-force events, I’ve seen drone operators drop water balloons on each other for a fun game of hide-and-seek. If you think that a civil conflict won’t see different sides dropping IEDs on each other, think again. Cartels are already doing this to each other on our Southern border. Any static position, no matter how temporary, must be camouflaged from the air, and that includes thermal.

First, hiding under tree canopy is preferable. You should also set up overhead concealment. If you use a tarp by itself, eventually that tarp will absorb some of your body heat and you will show through as a human-sized, human-shaped heat signature. It’s even worse if you drape the tarp directly on top of you, which does nothing at all after a minute or two.

The solution is to use a mylar space blanket or tarp. The reflective qualities of the mylar will not absorb your heat as long as there is at least a 12″ air gap between it and your body. This is important. Simply draping a mylar tarp on your body will transfer your body heat directly to it and it will do nothing to hide you, so you must find a way to suspend it over you.

GI casualty blankets off Amazon are pretty good for this. They have one reflective side and one green side. They even have grommets in them so you can suspend them between two trees/poles above you as with a tarp for a shelter. However, even the green side is still a bit reflective, and the grommets are somewhat weak. Badlands Rifleman attaches his to the underside of a USMC surplus tarp which is camouflaged. If you do that, all you must do is set up a lean-to, a-frame, or Royal Marine Rig with the tarp over your position, and you are completely masked from overhead thermal observation. I have a slightly different solution, which I will demonstrate in a future article.

I can personally attest that these GI Casualty blankets work incredibly well. When I was active duty, I had the opportunity to test one suspended 12″ over me as I lay in the prone. I was under that tarp all night, and in the morning one of our military-grade drones flew over me looking down with its thermal camera. I was completely invisible to it. I stuck out my leg so the pilot knew he was looking at the right spot, and only the exposed leg was visible through the sensor.

For more permanent positions, overhead cover made of logs, sandbags, and earth also blocks thermal imagers. In an urban environment, close the glass windows so thermal optics can’t see into your building.

Summary

Warfare is constantly changing. We must keep up with new developments if we expect to have a chance of surviving any future conflict. Thermal sensors, while potent, can still be defeated with a little bit of fieldcraft. Be aware of the threat and start training now. If you have your own thermals, go outside and experiment with them. Get an idea for what in your local area retains heat and could mask your thermal signature. Grab a buddy and try hiding from each other. If you don’t have thermals, come to a class and I’ll be happy to help you learn what works and what doesn’t. Registration for Team Leader I on October 1-2 ends this Saturday, so hurry up and shoot me an email to reserve your spot!