GPS (Global Positioning Satellite) units can be a useful aid if you're traveling in unfamiliar territory, but they're often better suited for the city than the boondocks. Three hikers at Zion National Park who depended upon their GPS for directions found themselves in Heaps of trouble.

Previous articles on the Traveler have pointed out that caution is needed if you're using a GPS unit in remote areas. Information may not be updated, the computer's suggested routes may not accurately distinguish between a good road and a goat track, and the level of detail shown on the GPS screen may not be adequate for the situation.

That "level of detail" issue came into play on a May morning several years ago in Utah's Zion National Park.

Three men set out on a one-day backcountry trip at Zion, intending to traverse a piece of fairly challenging terrain named Behunin Canyon. Their intended route would require eight rappels of up to 150 feet each.

If you’ve ever spent any time in the canyons of the west, you know that to anyone unfamiliar with the area, one rocky chasm can look very much like another. No problem for our trio--they had a GPS unit to help locate the head of Behunin Canyon.

In retrospect, this group may have been better served by a reliable standby, a detailed topographical map, to locate their starting point. I realize topographical maps are now considered by some to be old-fashioned, and they also require a bit of experience in translating all those squiggly lines into meaningful information—but they’re hard to beat for accuracy.

At a minimum, such a map or even a detailed written route description could have provided confirmation of the information on the group’s GPS unit. However, if they had used a map, I wouldn't have a story to tell.

Based on the hints already provided, it should come as no surprise that this expedition got off to a less-than-promising start. An inch may be as good as a mile in some circumstances, but not on a GPS screen (or a map) if you’re on a backcountry trip.

In this case the error on the ground was actually about a quarter of a mile. That’s the distance between their intended jumping-off point and Heaps Canyon, which the group located with the help of their trusty GPS unit, mistook for Behunin Canyon, and entered to launch their adventure.

Some of you who are in the “seen one rocky canyon, seen ’em all” school of thought may be wondering what difference that made. I’m glad you asked.

In contrast to their intended route, a trip through Heaps Canyon is described in very different terms by park reports: “a very difficult and technically challenging route. It should only be attempted by skilled and experienced canyoneers... a multi-day trip that includes swims through numerous potholes with water temperatures in the 40s and many rappels, including one of 300 feet."

That last bit of information is particularly important. If you start a trip equipped for only a 150-foot rappel and suddenly find yourself faced with one twice that distance, you are definitely in a Melancholy Situation, and you'll soon find yourself at the end of the literal rope.

When the men reached the first cliff, they failed to find the expected anchor points for their rappel. Here’s one more hint about mountaineering: If you plan to defy gravity, lean out into thin air to descend a steep cliff, and entrust your life to a rope (preferably two ropes, including your belay, or safety, line), it’s a really good idea to be sure the appropriate end of that rope is firmly attached to a very secure anchor point.

Our trio discussed discontinuing their trip at this point but instead created an anchor of their own and forged ahead. This decision is an excellent example of what I call macho mania, a close relative of the HOSS syndrome. Although it’s not limited to the male of the human species, this malady does occur more often in that group.

HOSS is closely related to that other underlying cause of numerous bad decisions: peer pressure. Put an average guy under the age of about sixty with at least one other person in a situation requiring even a hint of daring, and he will usually experience at least a brief desire to prove that he’s a “real hoss,” and therefore up to facing whatever challenge lies ahead.

There is a valid physiological explanation for this behavior that explains the derivation of the term HOSS—Hormones Override Sensible Solutions. The passing of years and/or successful escapes from enough close calls eventually diminishes this syndrome in most adults, but that was clearly not the case for our group down in the depths of Heaps Canyon.

Once they realized their mistake, the men were past the point of no return and were unable to backtrack to the canyon rim. I mentioned above that further travel through Heaps Canyon requires swimming through numerous potholes filled with very cold water, another situation for which the group was not equipped.

This would have been a really good time to call it a day, find a safe perch, and wait for rescue. The group had at least obtained the required permit from the park for this trip, so their failure to return as scheduled would have been noted. HOSS reigned supreme, however, so instead of cutting their losses, they pushed on.

Fast forward to the next day. The inevitable park report states that by then one of the men decided he’d had all he wanted of swimming through frigid pools; he climbed to a nearby knoll to await rescue. At last! A good decision...better late than never.

Violating yet another basic rule for any outdoor trip, the group split up, and the remaining two members forged on into the narrowest section of the canyon.

This little adventure was originally intended to be a single-day trip, so on the previous evening, the group had been reported overdue. Rangers began a search of their intended route in Behunin Canyon the next morning, but by afternoon concluded that the missing trio was not in that area. A helicopter was then brought in to search a wider area, an expensive step that should gladden the hearts of taxpayers everywhere.

The aircraft did prove to be the key, and all three men were located. A landing was definitely not possible in the narrow canyon, so necessary supplies and radios were lowered to the strandees to allow them to get through another night in relative safety and comfort. Since specialized gear such as thick wetsuits or drysuits is normally required to safely make this trip through frigid waters, rangers were surprised that the two were not victims of hypothermia.

On the following morning, additional equipment was lowered to the pair of “hosses,” which enabled them to complete the trip through Heaps Canyon on their own. The one man who had wisely known "when to say when" and stopped earlier on higher ground, was flown out safely by helicopter.

Although this saga in Heaps Canyon had a happy ending, there is a definite moral—or two—to this story, ironically provided by the name of the canyon where it took place. Don’t believe everything you read, including directions on a GPS unit. Most important, if any outdoor trip just isn’t going as planned, be willing to admit that fact and call it a day, before you find yourself in Heaps of trouble.

This story is adapted from the book Hey Ranger 2: More True Tales of Humor and Misadventure from the Great Outdoors © Jim Burnett and Taylor Trade Publishing, used by permission.