Frost on windowpane. Chicago, January of 1995.

Tree of light

Some things you can’t pencil into your agenda.

I stood in a forest at night under a quarter Moon so smudged by a sheet of altostratus that Luna looked like a cloud. The place was Kettle Moraine in Wisconsin, a month past Christmas of ’93; the mercury was a marrow-numbing 20 below zero. But these were factors I’d penciled into my agenda.

The most memorable moments on the trail are things I hadn’t penciled in: a tag-team of coyotes pursuing a pair of black-tailed deer on Mt. Diablo’s North Peak; crepuscular rays streaming through gaps in a massive oak on Mt. Tamalpais; marine fog at dawn whipped though Highland Ridge on a stiff west wind. Such moments aren’t boxes to check off a to-do list; they’re gifts, not achievements.

As the quarter moon broke the horizon on that minus-20 day in ’94, I decided to hit the trail and push the envelope’s frigid edge. I packed the essentials: a pastrami sandwich, Armagnac and a thermos of blistering coffee. I slipped layers over my torso and slid spectacles over my nose, hoping the frames wouldn’t freeze to my bridge. Yes, this hike was idiotic enough to be highly appealing.

In the Upper Midwest, you assault winter with recreation or cower indoors. I chose assault, but that winter had been quirky: too little snow for cross-country skiing; too much for hiking. I’d contracted an acute case of cabin fever and needed trail time. Never mind the mercury.

I hopped into my car and got the first good news of the evening: the engine started. Eighty minutes later I rolled to a stop at the Scuppernong trailhead north of Eagle. I stepped out and immediately felt the skin on my face tighten in the bitter air.

The trail had been dusted with a quarter inch of snow. Had it been a foot deep, my boots wouldn’t have noticed. Not much melts at minus 20 F. After 10 minutes on the trail I pressed a gloved finger to chin and nose. No sensation. I pulled my turtleneck over the bridge of my nose, losing the faint scent of pine needles but gaining feeling in my epidermis.

An hour later I rounded the northern arc of the trail through a grove of oaks and entered a prairie undulating south in shallow waves. Having escaped the forest’s sheltering friction, I felt the first hint of wind from the northwest graze my right cheek. I picked up my pace to get the blood churning.

Above, Capella, Rigel and Sirius pierced a sky washed pale by moonlight and streaked by altostratus gaining density. The other stars strained to break through. It was hard to look away from that sky, but something far down the trail, maybe 500 yards distant, caught my attention: a small orb of light.

Photo by mscornelius/Stock/Getty Images.

I descended the prairie’s next trough and lost sight of the orb. When I reached the next crest the picture wasn’t much clearer, except that the orb’s shape was more oval than circular and its light wasn’t solid and steady. Down the next swale I went, this time at a trot. At the top, 200 yards from the light, I found I’d only created more questions than I’d answered. I could make out a tree, not more than 10 feet tall – a tree emanating the softest of shimmering light.

I was stumped. The closer I drew, the dimmer the light fell, as if I were hurtling toward a galaxy that betrayed its true emptiness, the immense darkness between its stars, with greater vividness the nearer I approached.

The light disappeared below the final crest and I found myself running down the slope, a slope just steep enough to send me flying. I reined back the pace and climbed the final incline with impatient strides. When the light peeked above the crest, just 50 yards away, my puzzlement turned to anxiety. The tree was sparkling.

It was a perfectly ordinary scraggly young pin oak, but for one detail: from its bare branches a thousand slivers of light flared like meteors. I closed the distance, my heart pounding in my ears. Epiphanies are nice, I suppose, but I didn’t come out here to meet the Almighty in the form of a burning bush.

Finally, at a distance of 10 feet, the tree revealed its secret – something I’d never have thought to pencil into my agenda. Someone had been out here in December and draped the branches with tinsel. In the middle of nowhere. As the strands twisted in the breeze, splintered moonlight danced and vanished and danced again.

If a tree glitters on the prairie and no one sees it, does it radiate light? Yes, whether we’ve penciled it in or not. “Beauty and grace are performed whether or not we will or sense them,” wrote Annie Dillard. “The least we can do is try to be there.” So I stood there, straining to grasp the improbability of the convergence of moonlight and the silvery fire of tinsel warming that perilous air with beauty and grace, my belated Christmas gift from the universe.

May you be graced by the unexpected mystery made manifest this Christmas season. May the Father, whose intricacies of love glisten like the snowflake, cause you to shine with the brightness of the winter Sun. May the Christ Child, the small but growing light of solstice, bring you hope. And may the Spirit, like a current of wind across a frigid landscape, breathe steadily on the coals of your heart.

Beneath the surface of surf

At Pescadero Beach, a plunging breaker crashes against the rocks.

Californians are notorious for making waves. From flaunting alternative lifestyles on Castro Street to enthroning stars of the silver screen in Sacramento, we love to soak the unsuspecting body politic in the spray of our cultural cannonballs.

Maybe we’re taking the cue from the ultimate wave maker, a certain large body of water to our west. Year-round, along 840 miles of coastline, we get to see and smell the swell and scent of the mighty Pacific Ocean; get to hear waves, like breath, exhale onto the shore and inhale back to the dark lungs of the deep. And once in a while, tide and wind conspire to create that paragon of fluid physics: the plunging breaker. 

But what exactly is going on there? Why does a wave plunge? What physical forces produce the aesthetic event? And as a bonus puzzler: why do waves always roll in parallel to the shoreline?

To understand the inner workings of a wave, hold your breath; we’re taking it underwater. A wave isn’t primarily the movement of the surface of the water but the collective motion of water beneath the surface. If you’ve ever thrown a small piece of driftwood – or uncooperative Frisbee – onto a gentle incoming wave, you’ve seen this principle in action. The floating object rides up the wave crest’s leading edge and down its trailing edge with a slight forward, then backward motion. For its part, the wave rambles on toward the shore, leaving the object to bob atop the next incoming wave. In short, the wave moves toward the shore while the water on the surface moves up and down.

Boogie boarders test their mettle at Stinson Beach.

So what’s going on beneath the surface? Circular motion, that’s what. Once a wave gets organized out at sea, it resembles a long cylinder, like a roll of carpet in a warehouse. (The wave is actually a series of many rolls stacked on top of each other, decreasing in size the deeper they go.) A surfboarder knows this better than anyone. A breaking wave’s topmost roll forms the large tunnel along which the lucky surfer skims. When we say that waves “roll in” we’re speaking more than figuratively.

At a certain point in its tumble toward the shore, the deep water wave runs up against the ocean bottom, which causes two things to happen. First, as the wave brushes the bottom it’s pushed upward and its crest steepens. This causes the water at the crest to speed up. When the speed of the crest outruns the speed of the overall wave that supports it, the crest collapses as a plunging breaker. Imagine a slapstick comedian leaning nonchalantly on a cane. Someone sneaks up behind him and kicks away the cane, making him crash to the ground.

Parallel waves march in at sunset along the California coast.

The ocean bottom is also the culprit in our second cause of a wave’s collapse. When the water through which the wave spins becomes too shallow to allow the wave to complete a full rotation (that is, to get filled in with supporting water), the cane again gets kicked away and the wave falls on its face. But what a fall. If you’ve ever seen that translucent curved curtain strike a rocky cliff at the optimal gathering of energy, you’ll never forget it.

Finally, what explains the tendency of waves to approach the shoreline in parallel formation, like a well-disciplined marching band? Well, consider the marching band. That long, rolling cylinder zeroes in on the shoreline at, say, a 45-degree angle. One side of the cylinder’s length will feel the bottom first. Friction slows down that side, while the side out in deep water spirals along at its original clip. Like a marching band executing a wheel, the faster deep-water side rotates around the hinge of the slower shallow-water side till voilà! The wave marches home perfectly perpendicular to the shoreline.

Here’s wishing you a memorable escape at the coast, where breakers plunge and waves wheel – and your knowledge of the inner workings of these marvels makes them more dramatic.

Winter – gnawing the marrow

Devil's Peak, Royal Gorge, elevation 7,074'.

Winter couldn’t wait. A week short of the solstice, a snowstorm swept through the granite spine of the Sierra Nevada Range. Bear Valley registered 30 inches in the last 48 hours. The calendar belies it; the imagery clarifies it: black bears and big-leaf oaks lie dormant. Fangs of ice hang from the lips of cliffs and carpets of white weigh precariously on windward mountainsides. Winter is here.

For us west of Central Valley, the fee exacted for eight months of dry skies is four months of rain. No sub-zero temperatures crack our water pipes, no blizzards send our cars careening into ditches. Winter in the Bay Area: If this is as bad as it gets, we’ve got it good.

We Bay Area folk might wish our winters were more severe. According to Garrison Keillor, chronicler of Minnesota’s imaginary Lake Wobegon, harsh winters produce virtuous people. At the least, communal shivering discourages the vice of self-pity. “Winter is not a personal experience,” writes Keillor. “Everyone else is as cold as you are; so don’t complain about it too much.” And the physical challenges of winter – shoveling sidewalks, jump-starting dead batteries, pushing cars out of snowdrifts – provide ample opportunities for neighborly acts.

The naturalist Barry Lopez echoes Keillor’s take on winter. In his travels with Eskimo hunters, who live “in a world where swift and fatal violence, like ivu, the suddenly leaping shore ice, is inherent in the land,” Lopez was struck by the Eskimos’ acceptance of Nature’s hard knocks. “They have a quality of taking extravagant pleasure in being alive; and delight in finding it in other people.”

In the crucible of winter, our molten frailty hardens into a Promethean shape: resourceful and defiant. We bring down fire from heaven. Fire, in fact, has always been the chief weapon in our war on winter. Harnessing fire allowed us to emerge from the last Ice Age and pursue the woolly mammoth across the Arctic Circle into America. Tens of thousands of years later, the sparks thrown by those modest campfires have set the forest of our civilization ablaze, jumped the fire line and changed the face of the planet.

But there’s a catch. In the words of archaeologist and anthropologist Loren Eiseley, “The sorcerer’s gift of fire in a dark cave has brought us more than a simple kingdom. Like so many magical gifts it has conjured up that which cannot be subdued but henceforth demands unceasing attention lest it destroy us.” This applies not only to the fire of nuclear self-annihilation. Our modern version of primitive tinder and flint – coal, petroleum, natural gas, nuclear fission – might shield us from the ravages of this or that winter. But they cannot prevent the next Ice Age or global warming. They might, of course, bring them on sooner.

Wind-whipped ice razors on the Mt. Diablo summit.

If winter makes us tougher, it can also make us more thoughtful. Thoreau believed that winter promotes a more inward life. Standing on the banks of a frozen river, he imagined the human brain as “the kernel which winter itself matures.” Winter clears the mind’s clutter as it clears leaves from forest branches, giving our intellectual landscape a transparency that allows us to see through things. “The winter,” wrote Thoreau, “is thrown to us like a bone to a famished dog, and we are expected to get the marrow out of it.”

No matter how compassionately winter treats us in 2015-16, it’s clear that Nature has required us to submit to its terms. Be grateful for the challenge. If it’s a pass/fail test, we’ll surely pass. The greater achievement will be to embrace the cold rain and long nights, let them sweep into and through us, and find on the other side of the season a place where the first wildflowers grasp for the growing light, a place that without winter would be far less sweet.