Living in a place with the dubious honor of being the coldest in the world with a population over 500 prepared me for a lot of things; snow, ice, freezing rain, hail and the rare but oft-cursed thundersnow. It prepared me for weather so cold you wish it was warm enough to snow, weather so cold that it turned your breath into snow, and a wind that cut through the sturdiest hardshell jacket by finding the stitch-holes that hold the fabric together.
It did not prepare me for the mountains of Afghanistan.
A flat, desolate prairie punctuated by corn silos and truckstops is one thing; sure, the wind can howl unimpeded for hundreds of miles, but in Afghanistan, in some places, it snows uphill.
To understand fully the complexities of the terrain in that part of the world is, in a large measure, to understand everything about it. It shapes the wind and the water and the people.
The geography defines the weather, which defines the patterns of human habitation. The topography defines the specifics of roads and any trails and village placement. It is also the most important nonhuman factor in combat.
There are places where forty miles on a map makes a difference of thirty degrees on a daily basis, and ten inches of rain a year.
There are places where it snows uphill, because the warmer, moister clouds in a valley or plain below are blown up by pressure fronts into the chill on the mountain, and standing up there you can watch as the snow comes out of the tops of the clouds and blows upwards.
On a transport flight, if you're lucky enough to not be tied to the floor, or your tether is long enough, if you can look out to the East at altitude on a clear day, you can see K2. The roof of the world, they called it, in the Victorian age. The Pamir Knot, where the Pamirs meet the Hindu Kush. Dupree said in his Afghanistan, regarding the terrain here; "...'Tortured' is not trite. It is merely succinct."
Funny name, Hindu Kush. It means "Killer of Hindus". It's why the conquest always happened West to East, and not the other way around. The people in the plains to the East could not fathom what it took to cross the mountains; and for hundreds of years, thousands depending on how you interpret history, the Dravidian plains lived in mortal terror of the strange supermen who lived beyond them.
There are a few records of pre-Mongolian conquest from the East in the history of Afghanistan, but not many, and nothing that left a permanent mark on the artistic, linguistic or genetic heritage of Afghanistan as has any invasion of merit. Afghanistan stopped Alexander's conquest, and killed him to boot, but he still managed to leave behind a few cities and a pocket of descendants who bear his genes to the current day. But then, he wasn't coming across the mountains the hard way, either.
I wonder if that's what drove his men to mutiny? The burning Hell of the plains where nothing lives, and then a place where it snows uphill. They thought they were marching towards the end of the Earth, and they were right.