From a couple sites about Polar regions. Long parallel ridges in the snow formed by wind action.
No clue as to etymology. Not a spellingbee word. From article in TIME.
"It surface ripples with undulati;ng pressure ridges and solid wind hewn waves called sasturgi......"

Definition: zastruga, var. sastruga. sastruga (__________). Also zastruga; chiefly as pl. sastrugi (__). [a. G. sastruga, f. dial. Russ. zastrúga small ridge, furrow, f. zastrugát to plane, smooth, f. strug plane.] One of a series of irregular ridges formed on a snow surface by wind erosion and deposition, aligned parallel to the direction of the prevailing wind. 1840 E. J. Sabine tr. von Wrangell’s Narr. Exped. Polar Sea vii. 146 We were guided by the wave-like stripes of snow (sastrugi) which are formed, either on the plains on land or on the level ice of the sea, by any wind of long continuance. Ibid. 147 It often happens that the true permanent sastruga has been obliterated by another produced by temporary winds. 1878 E. L. Moss Shores of Polar Sea vi. 42 The sloping shore hills are barred with ‘sastrugi’–wind-made ridges of snow–but the abrupt scooped-out rifts between them are smothered over with fleecy powder in gentle undulations.

So would sastrugi also apply to the same effect on sand and sand dunes?

Not unless a Russian saw them.

It would be good to see a photograph of these sastrugi...I'll go goggling on google.

Dear WW: They aren't spectacular, The magazine article had a picture of them.
I'm reminded of another word I posted about a long time ago. There is a German word
for stairs "Treppen" that in Norwegian version is used to describe huge successive lava flows
which look like round steps. Look up "Siberian Traps". And there was the word "treppenwitz"
the clever retort that doesn't come to you until your on the stairs leaving a party, too late

http://www.johnj.com/pole00/image_html/image_roll208_res20_Img0060.html
A picture of ststrugi, plus a sundog. Not very impressive.

to use it.

What's a sun dog?

I wish I could look it up, but I'm here at school in between classes and only have a second to peek in.

Are all those lines across the photographs sastrugi? They're not much to comment on, are they? But nice word.

A sundog is the small circular prism-like rainbow you see in the sky at the top of the picture.

after evading a thousand rock sites here is a picture of a moondog.
http://www.flash.net/~storyink/starz/starpage.html