Life Expectancy

from my door, as high as the bottom of my window, allowing me no exit.
        Close up, it appeared huge, in part because it stood on enormous tires that added a foot to its showroom height, as though the driver intended to compete in a monster-truck rally.
        The Explorer churned forward, not fast but doggedly, tearing at the drift, climbing over it, but the Hummer paced us, angled into us. The metallic clunk of impact was followed by a shriek of tortured sheet metal.
        With advantages of size and power, the Hummer began to shove the Explorer sideways toward the rock formation along the western shoulder even as both vehicles continued crawling forward.
        I glanced out of my side window, up at the Hummer, trying to see the crazy bastard's face behind the windshield, as though something in his expression might explain why. Through the glare of headlights and roof-rack spotlights, I couldn't get a glimpse of him.
        One of our snow chains broke but continued to cling to the spinning tire, flailing loose links against the wheel wells and the undercarriage, rattling out a series of hard knocks reminiscent of gunfire.
        I couldn't negotiate the impeding wall of snow and at the same time attempt to accelerate around the Hummer.
        As I despaired of escaping him, an abrupt diminishment of resistance indicated that we were through the drift, and suddenly I had hope again.
        From his higher vantage point, our attacker must have seen what had been about to happen and must have tramped his accelerator at the penultimate moment. Instantly, as we lurched forward, so did the Hummer, jamming harder against us.
        To the west, the anomalous rock formation was gone, and the land dropped off into a woodland.
        Lorrie had bad news: "There's no guardrail."
        The Explorer slid far enough sideways that it must surely have been off the pavement, on the shoulder. As I tried to power past the Hummer and regain the roadway, we were forced counterclockwise. When we turned far enough, we would plummet backward down whatever slope lay beyond-a terrifying prospect.
        Lorrie made a sound half gasp, half whimper, either because a contraction wrenched her or because the thought of a backward plunge into unknown territory didn't appeal quite as much as did a roller-coaster ride.
        I let up on the accelerator. This changed the physics equation, and the Explorer shifted clockwise, straightened up.
        Too late. The right front end dropped sharply, and I knew we had been pressed to the outer edge of the highway shoulder. With the Hummer pushing relentlessly, the Explorer would roll, tumble side over side into whatever lay below.
        Counter to instinct, I pulled the steering wheel hard right, into the drop, which Lorrie must have thought was suicidal, but I hoped to use the Hummer instead of continuing to fight it. We turned ninety degrees as we hung on the brink, away from our attacker, until we were facing down a long snowy slope-neither gentle nor impossibly steep-stippled with pine trees receding into a wintry gloom that the headlights could not dispel.
        We started down, and I stood at once on the brake pedal, holding us at the crest of the incline. We could see where we were headed now, but I still didn't want to go there.
        The Hummer shifted into reverse, backed away from us, no doubt with the intention of ramming us from behind. At our angle, canted sharply forward, he might be able to tip us end over end into the forest below.
        I had no choice. Before he could ram us, I let up on the brake.
        "Hold on," I told Lorrie.
        The idling engine and gravity pulled us off the crest and down.
        To put distance between ourselves and the rifleman, we had nowhere to go but down. Judiciously, I pumped the brakes, trying to keep our descent under control.
        The broken chain tore loose from the tire. Other than engine noise and the faint clink of the other chains, the only sound was the shush of parting snow.
        This was a section of old-growth forest, the trees so immense, the high branches so densely interlaced into a sheltering canopy, that the accumulated winter snow was only twelve inches deep, less in some places. Likewise, so little sunlight reached the floor of these woods that undergrowth posed no obstruction, and the lowest limbs were far above us.
        Trees numbered fewer here than in a younger and