The Physics of Flow
We were on our second exploration of the backcountry of James Peak when it happened. For a brief interval I entered the “flow state” in a primordial and unprecedented moment of ecstastis. Like my occasional lucid dreams I flew high and free… but this time in real life.
We plummeted down the first run of untracked powder, wilting snow-covered pines contrasting with the reflected blues and shimmering whites of the sky and clouds above. Due to the uncontrolled backcountry area we were entering, I was primed to be aware of the snowpack, wind, temperature and exposure. I was highly observant to the sensations sent through the divining rod of my knees from the hidden reserves of blue water below.
I was in Utah for “Flow and Snow” a unique small-group experience led by Flow-masters, authors and practitioners Jamie Wheal and Steven Kotler. Along for the ride and carving turns ahead and behind the group were pro skiers Langely McNeal, Julian Carr and Lyndsey Dyer.
I’m not much for skiing with others – I like to ski fast and hard and I am impatient, but the cast and crew were all experts and even though there was some waiting, I enjoyed the camaraderie. My backcountry buddy was JP Scanlon and on the first trip down James Peak he went first and I followed his line a bit to the left. We were in and amongst scattered pines in untracked powder sheltered by shadows and it was light and billowy, easy to ski and required little in the way of skill. It was bliss and joy, we whooped and hollered… but due to the lack of challenge, it wasn’t flow - until I drifted to the left and entered the strange mix of snow at the crest of the ridge. Speed increased swiftly in the few turns I made in the stiffer, shallower cover but I also noticed an ability to set my hips and carve as well. I ran out of hill before I fully explored and vowed to return on the next run.
On our second pass JP exploded out into the lead leaving white contrails in his wake as he rocketed through the pines, whooping with joy. I was a bad ski-buddy and instead of following I traversed a bit to find the special snow-pack on the ridge from the last run. I tested the layers with my pole. It was unusual – very soft and light on top due to wind-blown cover, but with a steady transition to ever tighter, heavier and denser snow below – I could only push my pole 24 inches down before it became impenetrable.
I pondered for a moment: we had just been taught a lesson on snowpack layers and fracturing, but I found another, older lesson in materials science suddenly in my head like a déjà vu. In my freshman year of university a materials science professor, trying to recruit more students into the then-unpopular degree, held an exhibition at the physics tank. He shared a number of fascinating demonstrations of how materials act in unusual ways based on environment, temperature and other exogenous factors. In one of his first examples he put 3 rectangular chunks of ice perhaps 2 feet by 1 feet and 2 inches thick onto pairs of bricks holding them above the table. Then he recruited three volunteers. The first volunteer was given a ball-pein hammer to tap the first piece of clear ice. Immediately it cracked and fell into a half dozen pieces. “You see,” he explained, “this piece of ice is all the same temperature, so the cracks from the hammer propagate easily and hence the ice is highly fragile.”
The second piece of ice had some frost and whitening on the bottom, but was shiny on top, wet as if melting. “This piece of ice was just frozen from the bottom up. The bottom is 0 degrees, and top is 32 degrees.” He gave the next volunteer a regular hammer and the student took a whack. Nothing happened except for a few ice chips. Harder and harder the student swung and eventually the ice sagged, buckling in the middle, partially breaking. “You see, with different ice temperatures as a gradient throughout, the cracks do not propagate easily, and hence the ice is difficult to crack.”
He paused and brought out a hidden sledgehammer for the 3rd and final student and last block of ice. This piece of ice looked a bit like lasagna – a series of white layers were visible along the edge. He explained. “this block of ice has several layers of single-sheet newspaper frozen into it… Go ahead and take a swing,” he said to the student. The boy heaved the sledgehammer cautiously, but the ice didn’t wince. “Go ahead – take a full swing.” The student obliged and with a dramatic windup the hammer rose up high and swung full force into the ice… Which quivered, but held. After a few repeated swings, the ice eventually buckled in the middle, but remained in one piece.
“Fissure propagation,” explained the professor, “Is wildly different depending on the temperatures, inclusions and purity of the material.”
I looked at the snow again. 3 day old powder, repeatedly wind-blown, heated by the sun, cooled by the night and then layered again with fresh blown snow. Not only was I safe due to being on a ridge, I was safe due to the steady gradations of the snow from soft and light on the surface to solid and dense 18 to 24 inches down. This was “Flow Snow,” time to put it to the test.
I pointed my tips downhill and gained speed waiting for the right moment. As I reached a critical velocity, perhaps 30mph, far faster than typical powder skiing, I performed a move reserved for slalom and groomed runs – I set my hips into the turn, leaned hard and carved a turn.
My skis submarined for a moment, peeling through layers of substrate with help from the g-forces and then changed vectors smoothly as the denser snow below provided and equal-and-opposite reaction to the action of the shaped skis as they bit hard. I absorbed the g-forces as they compressed me low to my skis at the center of the arc and then began pushing back in syncopated slow motion, massive hydraulic thrust pushing core and quads into the snow. My horizontal trajectory swiftly reversed as I completed the turn where there was a corresponding and unexpected release from the vertical: time stopped as my tips suddenly exploded out of the snow-pack and I launched high into the air.
The feeling was nearly identical to a giant leap on a trampoline – the explosive forces generated by the hard carve, combined with the upward release from the snow catapulted me skyward… I shot into the sun, still leaning left at >50 degrees.
With fear and focus I immediately I entered the flow state… somehow I would have to reverse my tilt, in-air, to land at least vertically or preferably to begin a lean to the right. Fortunately the tail end of the arc had introduced some rotational energy into my mass and even as I reached apex of my unintended flight, my boots and skis rotated smoothly underneath me and I landed easily with a slight lean to the right, ready to begin the next cut.
I was now carrying even greater speed and in the flow state a sense of invincibility. I let the skis momentarily plane and then let the tips drop to submarine under the soft layers. As the snow began to give back I rotated hard to the right, hips leaning way down, skimming the surface of the powder as the dense snow at 24 inches gave back and I entered the compression of 3 G’s, even 4 G’s, traveling 35 mph and carving an arc with a radius of 15 meters or so. I leaned hard, compressed, reversed, released and then allowed the tips to explode back up out of the snow pack.
This time I flew on the wings of eagles, arcing high into the air with serious hang-time. During the release I again found my body rotating to prepare for the next landing from the boomerang of the resilient snow. At this speed, with hang times in excess of a full second, my tracks had 50 foot gaps between the turns*. *(a 3 meter leap and return to earth takes about .78 seconds, which at 35 mph or 51ft/sec = 40 linear feet. However, my vector was not flat – hence I probably landed at least another 15 feet down the slope before landing)
I pushed it a little harder each turn until I sensed some give in the snow. Then, for the next 15 seconds I executed a series of perfectly carved turns at the limits of the conditions until I ran out of ridge, flying high with each turn. I was, in those moments, either weightless, heavy, or rotating. Oddly, I was reading the book “Stealing Fire” and just after I wrote the above, I read the following paragraph, “’Weightlessness, weightedness and rotation are the nectar of gravity games,’” explains professional climber and film-maker Jimmy Chin. ‘They provide easy access to flow and that’s what keeps us coming back for more.”’
The ridge ran out and then back amongst the trees my speed quickly diminished as the ability to set edges evaporated and instead I bulldozed some beautifully billowy turns exploding into the valley where my fellow Flow-and-Snowers waited. I was speechless. In my head I was rewinding. I was remembering… thin-slicing the 3rd turn, the slow motion rotation in-air transitions from the explosive exit surrounded by my own detritus to the frantic moment where I had over-rotated and was flying completely sideways above the snow pack. In detached bemusement I remembered throwing down my right foot first to stabilize my landing, then returning to earth with perfect aplomb already 30 degrees into the next lean.
I was I a deep reverie as we made the traverse down James Peak. I hadn’t just skied… I had flown like an eagle, banked like fighter pilot. It was, in the lexicon of “Stealing Fire” “ecstasis”. In my own terms it was 20 seconds worth a year…
I have tried, on several occasions to describe these moments verbally, but failed to capture the essence. Hopefully I have come closer here.
Postscript: The ice for Short track speedskating uses these same materials science principles – the best ice is as follows: 1.75” thick. 17 degrees at the bottom, 32 degrees at the top, with a steady gradient interrupted by thin slices of resurfacings along the way and a surface air temperature of 52 degrees and a humidity of 15% to keep it slick, shiny and provide some bite. This ice allows a short track speed skater to enter a 25 meter corner at 31mph and 2 seconds later exit that same corner at 31mph going the exact opposite direction. V2/r gives the math for the g-force calculation, and concludes that a short track speedskater hits 2.7 g’s in the corner – effectively tripling their body weight. The space shuttle takes off at 3 g’s. So breaking it all down, a 170lb short track speedskater at that speed is doing the equivalent of a 500lb, one legged squat from deeper than 90 degrees, while leaning over at 68 degrees all while balancing on an 18” long, 1mm wide blade, on ice, heading directly at a wall.
Skiers have the benefit of longer blades and two legs.. The turns I was making on James Peak carved a shorter arc at a slightly higher speed, creating even greater g-forces – potentially in excess of 4 g’s and creating potential energy released as kinetic energy and the subsequent flight. A refrigerated hill and “with a snow-zamboni” could potentially recreate these conditions…