Sastrugi are parallel wave-like ridges caused by winds on the surface of what?

I'm exhausted, but I'm making steady progress every day," he said from his satellite phone on 20 December - Day 47 - as he camped amid a storm and massive ridges of ice and snow known as sastrugi. After a day which was like being "in the inside of a ping-pong ball" O'Brady said he was grateful to have negotiated the wavelike ridges of hard snow and ice in low visibility without having broken a leg.

Setting off through the Drake Icefall and Patriot Hills, the team of four vehicles -- the Santa Fe and three support trucks -- took three days to cross a featureless landscape studded with sastrugi ice structures, delicately picking their way around crevasse fields they had been warned about.

Sledging conditions varied from a satisfactory firm snow surface, to smooth, wind-polished ice, to damaging sastrugi and vast patches of ice with embedded, but protruding, particles of sharp pebbles.

Liautaud and Stoup arrived at the geographic South Pole on Christmas Eve, having faced gale-force winds, temperatures that dipped below -50 degrees Celsius (-58 degrees Fahrenheit) and three-meter-high sastrugi, or frozen waves in the ice.

Throughout his solo expedition, Richard faced the brutal Antarctic elements of white-outs, windchill and snow drifts called "sastrugi" and had to pull all his supplies in a small toboggan, which weighed about 68.2kg (10st 7).

Throughout his solo expedition, Parks faced the brutal Antarctic elements of whiteouts, windchill and snow drifts called sastrugi and had to pull all his supplies in a small toboggan, which weighed about 68.2kg (10st 7lbs).

we proposed a model of a Sastrugi surface over layered media [5], values of V can be as large as -20 K ~ 10 K due to total internal reflections from lower layers if given the upper layer's permittivity [[epsilon].sub.1] larger than the lower [[epsilon].sub.2].

The soft, deep snow and concrete-hard "sastrugi" snow forms caused the Advance Party's progress to slow, but after three days they safely reached the Lake Ellsworth drilling site.

Sastrugi are long-term features found in both polar regions.