Another tidbit from the (excellent) Peter Hessler New Yorker piece (archived) I quoted yesterday in connection with “Ouray”:
It had started snowing the previous day, and it was still coming down softly. Nordquist stopped at a series of platforms that tracked the snow’s height. He carried a device that measured the amount of water in the snow, and he also relied on reading the landscape. “You can look at a slope and see if it’s been wind-sculpted,” he told me. “I’m looking to see if it’s loading from a fetch into a start zone. A fetch is the back side of a hill. A fetch is usually where snow is coming from. A lot of times, you can see big plumes coming off a peak.”
Of course I was struck by this use of “fetch,” and immediately turned to the OED, whose noun entry (from 1895) has a fair number of senses, but not this; the closest is 3.b. “More generally: the expanse of water over which the wind blows before it reaches the point of observation (on the water or at the water’s edge); the distance that waves can travel continuously without obstruction.” But that’s not really very close. Wiktionary has basically the same set of definitions. Is anyone familiar with the sense “the back side of a hill”? (I might add that the etymology isn’t pinned down; OED: “Old English fecc(e)an; according to Platt […] and Sievers an altered form of fetian […], the originally syllabic i having, it is supposed, become consonantal, and the resulting combination /tj/ having developed into the closely resembling sound expressed by cc, i.e. either the geminated palatal stop, or something between this and its modern representative /tʃ/,” which doesn’t exactly inspire confidence.)
I can’t resist pointing out that the fiction in the same issue is “Narrow Escape” (archived) by… Aleksandr Solzhenitsyn! Their introduction:
In 1948, Aleksandr Solzhenitsyn, who was then twenty-nine and incarcerated in a Soviet facility—serving an eight-year sentence for having criticized Joseph Stalin in his private correspondence—began writing an autobiographical novel titled “Love the Revolution.” The novel, which was never completed, was published in Russia in 1999, and will come out in English for the first time later this year. This passage, adapted from the first chapter of the novel, is set in Rostov-on-Don, in the summer of 1941.
It’s pretty good, and I may have to look at the novel someday.
I don’t think he’s defining but just describing there. He’s using the nautical sense of fetch where if you’re the observer in the sailboat, the fetch where wind builds before hitting your sail is upwind of you. He considers his hill-fetch as being behind (upwind of) the interesting features he’s talking about.
After all, I don’t think hills really have a back side, so you can only define something as the back side of the hill based on your narrative frame of reference.
TL/DR – he’s using an abstracted nautical definition of fetch which means simply “area where the wind builds without obstruction.”
Agreeing with Ryan:
“Fetch” is used in oceanography as one of the factors that determine the size of wind waves (waves generated by wind rather than currents or other factors). In this explanation from NOAA, fetch is “the uninterrupted distance over which the wind blows without significant change in direction. (For example, storms of equal size can generate much larger waves in the open Pacific Ocean as compared to the other oceans due to the long open distance of water.)”
See also the Wikipedia page for “wind fetch.” So in land situations as in the New Yorker piece, it’s not so much the back side of the hill, it’s the unobstructed field or plain across which the wind is driving snow and then forming a plume, as described, where the terrain drops off. In many places, you get the biggest snowdrifts where the fetch is interrupted by something that creates a lee area where snow accumulates — could be a house, a hedge, a snow fence, etc.
That makes perfect sense — thanks to both of you!
I didn’t know fetch has actually happened.
Martin’s longer description explains why snow fences along roads work. The windblown snow from a long fetch goes over the fence, accelerating over the peak because its passage is constricted, then decelerating, which means some of the snow drops, creating a drift where you want it rather than on the road.
Dunes form downwind from sand-colonizing plants for the same reason. If enough plants die (because you let your kids trample them), you get a blowout – the windspeed at the constriction whittling the dune down.
the back side of a hill
Inevitably, I am reminded of the Kusaal zuor la gbin “the hill’s arse”, which refers to what English, somewhat more prudishly, calls “the foot of the hill.”
And the wind that blows from the arse of the hill is a foul wind indeed!