Winter's Unseen Trap
December 11, 2013
- This story and more in the December online edition of Knowledge Magazine - the Official Safety Magazine of the U.S. Army.
FORT RUCKER, Ala. (Dec. 11, 2013) - As an officer and aviator in the U.S. Army, I - like most of you - have been exposed to a significant amount of safety training. We've all learned that the unseen hazard is oftentimes the most dangerous. For example, Field Manual 3-04.301(1-301), Aeromedical Training for Flight Personnel, highlights Type I (unrecognized) spatial disorientation as the most dangerous because the hapless aviator has no idea they are disoriented, and thus, takes no action to correct the danger facing them. Carbon monoxide is similarly insidious. Whether it is exhaust leaking into your vehicle, or perhaps a propane heater warming a tent, carbon monoxide takes its prey with no warning. However, this article is not about spatial disorientation or carbon monoxide. There is another hazard that's similarly treacherous and just as veiled. Unfortunately, I found myself in its trap on my way home from drill one weekend.
It was a pleasant and cloudless Sunday afternoon on a drill weekend, a welcomed change from the sub-freezing, overcast, low-pressure area that had blanketed the Keystone State just a day earlier. Now, south central Pennsylvania was awash in sunlight, and the mercury had peaked near 40 F - improved weather indeed. Following formation, I made my way to the parking lot that had been cleared of the foot of snow that fell the day prior. I hopped in my Toyota pickup, fastened my seat belt with a reassuring click and set out on my hour and 10 minute commute home.
As I made my way south down the highway, the cruise control set at 65 mph and a local news station emanating from the small dashboard speakers, I looked forward to the Sunday evening dinner at my parents' house. Mom was preparing lasagna, and my brother was heading over as well. It was setting up to be an enjoyable end to a busy weekend of training. After 55 minutes of driving, I flicked up the stalk on the steering column, signaling my exit from the highway and my entrance onto the state route that would carry me to a warm plate of lasagna just 10 minutes away.
When I entered the state route and accelerated, something to the left caught my eye. I glanced through the light tinting of the driver-side window and saw the bright-orange digits of the local bank clock, which read 5:30 p.m. Then, in typical fashion, the time was quickly replaced by the outside air temperature - 34 F. I thought nothing of it, but, in hindsight, should have.
As I left the suburbs and entered the country, the sun had just slipped behind the hills. The vibrant orange of the sky and white of the fields was being sapped away, leaving only cold, gray dimness. I watched as familiar landmarks passed by - the old cemetery on left, the small business that specialized in flagpoles and signage on the right and the dilapidated wood barn that leaned awkwardly to one side as it strained under a heavy load of decaying hay stored there decades ago. I rounded the barn and entered a mild right-hand turn that was followed by a slightly sharper turn to the left. During normal road conditions, this turn was not so sharp as to require slowing down. Unfortunately, the road conditions were not normal.
I completed the left-hand turn and had just straightened the steering wheel when something felt odd. My faithful truck was not heeding my inputs. The truck was not straightening. I thought, "Is this just my imagination?" It was barely perceptible; yet, there I was, slowly - but unmistakably - approaching the double-yellow line. I tweaked the steering wheel a little more to the right to attempt a correction, but the truck continued to disobey.
As I crossed the double-yellow line, my hands gave up and my feet went into action, mashing the brake to the floor. Nothing … just sliding along. At this point, I was in a 3,000-pound version of one of those 25-cent kiddy car rides in front of the local grocery store, complete with an ineffectual steering wheel and brake pedals installed for entertainment purposes only. I was three-quarters into the oncoming lane and continuing my intrusion when a red Ford Escort, driven by a woman in her 50s, crested the hill not 400 feet in front of me. The next three seconds seemed like an eternity. When the countdown ended, the indescribable forces on the body and the agonizing gnashing of metal began.
I remember standing outside my mangled truck with someone. They were encouraging me to lie down, but I resisted. I glanced around painfully. My body ached all over. People gathered. I stumbled toward the Ford Escort. That same insistent person again asked me to lie down. Once more, I resisted. At the Escort's driver-side door, with shattered glass crunching under my combat boots, I bent over and peered inside to ensure the woman was all right. I was expecting she would be -- after all, I was ambulatory. However, she was not all right. Her legs were broken badly beneath the collapsed dashboard and she had a nasty gash in her forehead.
I was pulled away and taken to the side of the road by a passerby who happened to be a paramedic. I remember the Jaws of Life tearing at her car in an attempt to release her from the jagged metal cabin. I remember the helicopter landing in a nearby field, awaiting her extrication. I remember a state police officer stepping out of his cruiser and slipping on the pavement, nearly falling, as he approached me. I remember people murmuring and looking down at the road surface, motioning with their feet as if feeling for something. I remember someone saying the words "black ice."
Black ice had trapped me. It was just as deceptive and dangerous as Type I spatial disorientation and carbon monoxide. You don't realize you are in a deteriorating situation until it is too late.
So how can you avoid this dangerous winter hazard? Let's use the risk management process. The first step is to identify the hazard. But that's a problem. Like carbon monoxide, black ice is very difficult to detect. The road simply looks wet. Actually, it was wet at one point - until the temperature dropped or the sun went down, forming a thin, translucent glaze of ice. So, unless you plan on stopping your vehicle every 20 feet to feel the road, identifying black ice directly is not practical. What we can do, however, is identify the conditions leading to the formation of black ice.
In order for ice to form, there has to be a source of moisture. Anything that could make the road surface wet, or simply damp, is all it takes. There are too many to discuss here, but rain, mist, flurries and water runoff are likely sources. So what caused the road to be wet on the afternoon I had my accident? Remember, the skies were clear blue the entire day. A large amount of snow did fall the day prior, and although the road crews and the sun had completely cleared the roads, there were numerous piles still along the shoulders. Because of the relatively warm temperatures the day of the accident, the piles of snow began melting and running across the road surface, varnishing the black asphalt in a thin glossy film of water. The first condition was met.
The second condition needed is freezing or near-freezing temperatures. Take note that I said "near-freezing" temperatures. It is possible for black ice to form even if the air temperature is several degrees above freezing. This can occur if the air warms suddenly after a cold spell that has left the surface of the roadway well below freezing. In other words, the air is above freezing, but the road is not (this is why some late-model vehicles will alert the driver to the potential for hazardous road conditions, usually at about 35 F). In my case, the road was probably just above freezing during the day because of heat from the sun. But as soon as the sun was low on the horizon, shadows fell and the water runoff froze.
Now that we have identified the hazard, let's complete the risk management process. Using Figure 1-4 in FM 5-19, Composite Risk Management, and given the conditions above, I would assess the risk at high to extremely high. When developing controls, you might reduce your speed, travel earlier in the day when temperatures are warmer, select a different route home and/or use studded winter tires (although these still may not prevent sliding). You might even want to consider avoiding the drive all together and staying in base lodging or a battle buddy's house if available. It is better to arrive safely the next day than not at all. And, whatever you do, wear your seat belt. I firmly believe I would not be here today without my seat belt. Finally, make your decisions, implement your controls and continue to supervise and evaluate throughout your chosen course of action.
Black ice is a sinister, unforgiving and potentially deadly winter hazard that is almost impossible to detect while driving. By identifying the conditions leading to its formation and using the risk management process to reduce the risk, you can likely avoid sliding into its trap.