Temperatures are supposed to be in the 50s all week and hardly even freezing at night, so vague hopes that ski areas down in our neck of New Hampshire might open by Thanksgiving are disappearing. (You can’t make snow at that temperature, no matter how good your equipment.)

So let’s take solace in looking at this physics paper - one of the finest I’ve read in ages - which analyzes the movement over time of moguls on a ski hill, and finds that they move uphill:

A specific representation for the erosion–deposition wave W at position x created by a skier n may be given by the sinusoidal form W_n(x) = a sin(2πx/2r_n + ϕ_n), with positive W corresponding to deposition.

Anyway, the result is that as a skier turns on a mogul, snow is scraped from the bottom of one mogul to the top of the next one, having the overall effect of “moving” the moguls uphill over time. And this, my friends, is the kicker:

Measurements show that recreational skiers expend about 20–25 kilocalories per minute. Skiers spend roughly 20 seconds of actual time skiing (as opposed to huffing and puffing) when traversing a 100-m mogul field such as the one shown here, at Riflesight Notch in Colorado. That means a skier expends 8 kcal in a run. About 10 skiers go down Riflesight Notch each hour, and the mogul field is open 50 hours per week for five months. So there are about 10 000 runs down Riflesight Notch per season and 80 000 kcal expended. The field has about 200 moguls; that comes to 400 kcal per mogul each season. Since moguls move about 10 m uphill over the course of a season, each one requires 40 kcal/m to move uphill. More prosaically, skiers expend half a light beer for every meter of uphill mogul movement

Tags: skiing