“Reality is that which, when you stop believing in it, doesn’t go away.”

– Philip K. Dick

Long winters ago when my son Jack was still a boy, we were driving along Route 9 to Unity a few days after a snowstorm. The road was bare, mostly, but sub-20-degree cold had been on for what seemed like weeks, and so broken ridges and mini-mesas of ice were cemented on the road like huge barnacles.

You know what that’s like. It’s not snowing, so as long as you keep your wheels more or less in the tracks where the pavement appears to be bare, you think you can sail along like it’s endless summer.

Still, I kept it under 50 for safety’s sake because, after all, my 7-year-old son was riding happily beside me.

Funny story, it turned out.

In front of Espositos’ pottery shop we were suddenly going sideways. How this could have happened, I didn’t know, and how it turned out the way it did I understand even less. Because coming directly at my driver’s side window were a car and a pickup truck. Or rather, my driver’s side window was sliding directly at them.

I’m pretty sure my hands and feet switched instantly to skid mode, which after nearly 30 years of driving on two continents I had of course experienced and, as I believed, had the knack of. But I don’t actually remember it. The next thing I knew, we were jolting backward into the snowbank in front of the pottery shop.

I looked over at Jack. “Are you OK?” I said. He said yes. His eyes were big, but it was less because he was scared and more because he wanted to scramble out and see what non-Euclidean angles the outside of the car had ended up in. He couldn’t open his door because the passenger side was wedged into the snowbank. So he crawled out the driver side after me.

By then the oncoming car and pickup had stopped to see if we survived. Faces were peering at us with real concern, because that’s how most people get in dangerous circumstances. Not all, but I’m coming to that. The guy from the car took my arm to help me out and asked if we were OK.

“Yes,” I said, “but how?” He shook his head in equal disbelief. How our car could have been sliding directly at his grill in the left lane but then somehow change direction, re-cross the road to the right lane, and plow backward into the other snowbank unscathed, neither of us could remember or even visualize. Twenty years later, I still can’t. I don’t know how the physics of why we all didn’t collide and end up dead that afternoon worked. It makes you give serious thought to the concept of “angels.”

What holds vehicle tires to the surface of the road is friction. It turns out the scientists who study tires on icy pavement refer to two kinds: wet friction and dry friction. Ice normally has a thin layer of liquid water on its surface, which seems counterintuitive, but the liquid is the reason the ice is slippery. Ice in a temperature right around freezing (32 degrees Fahrenheit) and calm air has a relatively thick layer of liquid water (wet) and is very slippery. When the temperature drops below about 25 and down to single digits, that layer of liquid gets thinner, and the ice is less slippery. Less slippery still, if wind is scouring it.

The friction needed to brake the car has three components, as indicated by scientists at Virginia Tech: the ice and ambient conditions; the tread and composition of the tires; and the vehicle itself. The little Mazda that long-ago day was only a few years old, and the all-weather tires were sound. But the surface texture of the ice was no doubt smooth after the previous cold week or more of vehicles grinding down the ridges. The temperature that day had come up toward freezing. So we were driving on patches of ice with a pretty low friction coefficient. And it’s not unreasonable to think black ice had invisibly formed on what looked like bare road. In front of the pottery shop, the friction let go.

I was thinking about this a couple of weekends ago while I was driving along Route 3 in China just before the blizzard. It wasn’t actually snowing yet, so there was an illusion of freedom to sail. But in the roadway were ridges of ice, just like in long-ago Unity, and stretches of slightly thawed slush from snow that had fallen earlier. Wet ice. Slippery. I kept my speed around 45, which is the statistical cusp between crashes and crashes with serious injury or fatality.

Up behind me came a van. Not the most agile of vehicles, especially on ice. Undeterred by, or oblivious to conditions, the driver tailgated me for several miles. On one of the “slower traffic keep right” hills, the right lane was an undisturbed layer of half-frozen slush that undoubtedly concealed shelves of ice with developing layers of liquid water. So I kept to the tracks in the left lane where everybody before me had gone too.

The van driver gunned up the right lane through the slush, got enough momentum to pass me before the right lane ended at the top of the hill, and shoved his arm out the window with his middle finger up as he cut in front of me and took off going at least 65. It seemed like dumb luck when in the next 10 minutes I did not come upon a crash.

Of course, I have no idea what that van driver did or didn’t understand about icy roads. Don’t know whether he was a daredevil risking everybody else’s life and well-being just for the hell of shoving recklessness in everybody else’s face, or just an ignorant fool with no functioning relationship to the real world of ice, or both. The thing is, those were the only two possibilities I could think of, and I was on the same road with him.

That guy probably votes, I thought. I spent the rest of my drive to Augusta trying to tame a low-grade panic induced by the sudden understanding of how icy the roads have actually gotten this winter.

I don’t know what I think about angels, to tell you the truth.

Dana Wilde lives in Troy. His book “Summer to Fall” is available from North Country Press <http://www.northcountrypress.com/summer-to-fall.html>. You can contact him at naturalist1@dwildepress.net. Backyard Naturalist appears the second and fourth Thursdays each month.