The day started clear and bright as the hikers left the trail head near Newport, Oregon. The temperatures were to be moderate most of the day with slight cooling in the evening. They pressed on determined to reach the summit before twilight. After reaching the summit at dusk, the group started to make their way back to the trail head as fog began to roll in. Within an hour the darkness was becoming a problem and the safety of continued travel became questionable.
So what are some basic considerations for night time travel and navigation in the backcountry?
First, let us consider that we are not in a “lost hiker” scenario. If lost, the best thing to do is to just stay where you are. This makes the job much easier for the searchers.
Further, recommendations are based on the concerns and issues of hiking when it is really dark, not during the period of a full moon with some ambient light.
One of the key factors in this situation is to have an understanding of the physiology of the eye. Our eyes are designed to provide optimal performance during periods of light. The components of the eye (the retina, rods and cones) are arranged specific to their function. The cones are the discriminators of fine detail and color. Cones are the most effective in light, and are located near the center of the eye interior. In complete darkness, a cones’ effectiveness is significantly reduced. Rods are located on the periphery of our interior eye, are not fine detail discriminators and have a higher sensitivity to low light levels. Rods are important to our night time vision.
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