Snow business.

The wet bulb reads 23 degrees at 0900 this morning. That’s 29 degrees warmer than the start of my day just five hours ago. I waited until the sun was up for a bit before I hiked up to retrieve the game camera that Shelly and I put on a trail up east of Rogue Manor West. It’s the first week of January 2021 and the deer friends are already dropping their antlers. We document our deer herd, their antics, and their annual physical growth and livelihood with our game cameras (which also records and the other animals that call our piece of Gunnison backcountry home).

One would suspect that the biggest danger of this daily hike would be the occasional surprise interaction with a cougar or perhaps a bear. These interactions are rare and you can prevent being surprised in the wild by following basic situational awareness principles.

There are three basic dangers that come with any mid-winter jaunt into the frigid outback.

First; avalanche danger. Each year in Colorado Snow avalanches occur in the high mountains and take the lives of both wilderness experts and snowbound neophytes. Avalanches come as the result of heavy snow accumulation on steep slopes. They can be triggered by changes in temperature, too much snow, or the vibrations caused by hikers, skiers, or machinery (like snowmobiles or quad runners).

Next; slip and fall dangers. The more a trail is utilized, the more the wind whips across the snow rounding edges and creating perilous spots posing hidden dangers borne smoother than the post-Zamboni ice at a Detroit Red Wings game. Each year over a million Americans are injured by slipping and falling on ice or snow. Of these almost 17,000 people die from these injuries.  

Finally; snow blindness dangers. Snow blindness is photokeratitis. In street speak it’s a sunburn of your cornea. While hiking without eye pro (eye protection) the unfiltered UV light from the sun hits the cornea (the transparent out layer of the human eye) and if unchecked, can cause a painful disorienting burn injury.

Disorientation can kill you, too.



It only takes an hour to hike up and back which is more than enough time to succumb to the effects of snow blindness. Combine the disorienting effects with your anticipation to get back home and out of the cold, and now, the light. You wander off-trail, knowing in your heart you are still heading the basic direction home, just a shortcut. Now the weather turns nasty, you slip and fall or some other malady distracts you further. A recipe for danger.

It’s a little-known fact that day hikers are more at threat of dying while hiking than those planning on a long haul. Think about it, research demonstrates that 43 percent of those who had to be rescued from the wild began their hike without the basic food and emergency gear they would need to rescue themselves. That’s almost half. A large number of that same group never make it back home.

The more vulnerable you are, the more danger you will likely face. The higher the level of danger the more essential your mitigation efforts need to become.

Basic human vision.

Let’s talk vision and vulnerability.

The key to human vision is light, motion, and edges. When you lose those (as in snow blindness) you lose much of your ability to sense-make your environment. The part of your brain that regulates your vision takes up the entire rear of your skull! Primates, which include humans, have the ability to distinguish colors. This is essential to survival because it allows us to be able to find food and locate someone with which to procreate, a “mate.”

At the back of your eye there are rods and cones which help you regulate light that creates color. For example; the rods don’t process color vision, they allow you to ‘see’ in a gray, black and white range with low levels of acuity. You ‘see’ by comparing objects against their environment. This makes sense because humans weren’t designed to operate for long periods of time in no light or low light environments. Cones work differently. They are placed much more closely together and allow both color vision and much higher acuity. Your fovea – the object in your eye that allows you to make visual sense of your operational environment – has no rods, only cones.

HG couldn’t see well.

When HG Wells wrote ‘the Invisible Man’ in 1897, people were drawn to the science fiction elements. Being a fan of Wells, I was drawn to the elements of loneliness that ‘Griffin’ (the main character) feels after his optics experiments render him invisible.

Those who truly understand vision understand that an invisible human would be blind. The lens at the back of the eye and optic nerve needs light in order to create the message to the brain. A transparent lens means no light with which to form an image and therefore no message would be transmitted. Add to this the fact that images are perceived upside down and backward. Your vision is a wonder and you need to admire (and protect) it!

Visible light.

Our ability to see in daylight or well-lit conditions is referred to as Photopic Vision. Our cones rule, we can detect the differences between colors on the visible (ROY G BIV) spectrum and we have much better resolution (the ability to see object more clearly) than in low or no light conditions.

Our ability to see in no light or low light conditions is known as Scotopic Vision. From the Greek ‘Skotos’ and ‘opia’, literally, “dark condition of sight”. Here, the cones are rendered non-functional and the rods rule our black, white, and gray vision. Remember, I said “see in no light conditions”, even when there is no light, your eyes can see motion and edges that will allow you some sight. 

Then comes the most vulnerable and dangerous. Your Mesotopic vision (also referred to as ‘Mesopic’). Each day at dawn and dusk your brain needs to “reboot” not unlike a computer, allowing the rods and cones to switch dominance. This period is almost dark vision and almost night vision – and therefore not perfect either. This creates a situation where you could miss threats directed at you. It is the primary reason for military reveille and ‘stand to’.

Mesotopic conditions, much like being bedazzled by too much light can make you make mistakes.

Military forces learned long ago that human vision could be fooled more easily during these times; the evolved ones reacted by “attacking at dawn” or criminally burgling by night. How important is it to the military? They developed EENT and BMNT (conditions that are related to all military personnel each day). EENT stands for ‘end of evening nautical twilight’ or dusk. BMNT refers to ‘begin morning nautical twilight’, or dawn. I’ve never attended a professional military briefing where BMNT and EENT weren’t discussed.

Pretty flashy.

Both law enforcement professionals and the military use flash-bangs to disorient suspects. These grenades are non-lethal weapons that, when thrown, explode loudly causing a bright, blinding light flash and a deafening thud. Here, again, disorientation proves dangerous, or at least distracting enough to allow the coppers to cover ground and surprise or disarm the violent suspect.

Practical eye protection.

Is high-quality eye protection necessary?

Absolutely! The protection provided by higher-quality optical lenses offer not only better UV protection but they can cut down on polarization and allow a better overall visual experience.

Polarization in vision refers to vertical openings in lenses that block out the horizontal light that is bounding around you glaring at your eyes from shiny objects and water. Good lenses can also protect your eyes from projectiles or some shrapnel that might be flying about your environment. If you lose an eye or diminish your vision you are at a survival disadvantage in many circumstances. It’s important to “test drive” eye protection prior to purchasing. One major mistake is not accounting for the essential nature of your peripheral vision.

Central or peripheral vision?

Earlier I mentioned the importance of the fovea without specifically defining its purpose. The fovea centralis is responsible for your sharp, central vision. The type of vision you need when you are reading, driving, or doing detailed hand-eye coordination type activities. If you aren’t using your central vision, you are using peripheral vision. Peripheral vision allows you to see to your front and sides without orienting or turning your head. Coupled with its ability to sense motion, it allows you to see objects ‘out of the corner of your eye’ so you don’t run into things.

Simply put, the ability to use your central and peripheral vision, coupled with your eye and brain’s ability to detect light, motion and edges in your environment allow you to operate and complete your daily essentials (fornicate, fight, feed or flee) when used with or without your other senses.

There is no Sixth Sense.

Sight, sound, touch, smell, and taste are the five senses bestowed upon humans. I’m often asked which is the ‘master’ sense. I usually respond that it depends on the situation. For example, much of your brain relies on your vision. Yet vision is much less important when you are in bed at night and there’s a fire raging in the utility room. Therefore, the best answer is that, when combined, your 5 sense do an amazing job of keeping you safe. 

I do balk whenever someone talk about a ‘sixth sense’. Not the scary film with Die Hard and little Haley Joel Osment, but the perception that there exists some intuitive ability allowing above normal perception and awareness in certain humans over other people. Total falsehood. Some people are merely more in tune with their 5 senses and when they are more situationally aware, they seem to detect things like emotions within an environment faster and with greater acuity.

Keep your head on a swivel.

We’ve all heard the advice to keep your head on a swivel. Sometimes we don’t understand just how important that piece of advice is.

First, in low light, looking at your environment while swinging your head and eyes (on a swivel) in a figure-eight will allow you to sense your environment better and ‘see’ items even in the near-complete dark. The reason is simple, once the rods take over, there is too much distance between them to see your environment clearly. That’s why when you look directly at a star in the night sky it disappears. There aren’t any rods there with which to define your perception.

Next, by keeping your head on a swivel, in any light condition, you are allowing both your central AND peripheral vision to take items around you into account. This makes you more aware – processing more environmental information with which to determine danger.

So What?

Protect your vision, increase your situational awareness by enlisting more of your visual field, and understand WHEN your vision is most vulnerable. This will ensure that your safety isn’t compromised. When I faced snow blindness, the dangers of missing avalanche, wild animal or slip and falls cues INCREASED making my simple hike up and back much more dangerous.

In a future episode I’ll touch on optics. Today, I briefly covered eye protection. Ensure that you are putting away money each week towards a good pair of eye pro that you can wear each day to increase your safety and protect your essential vision.

You can’t defend against what you can’t detect!

Training changes behavior.


  • Greg

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