CLIMATE OF THE McMURDO DRY VALLEYS REGION (NSF publication)

Mean annual sea-level air temperature around McMurdo Sound is -20 degrees C. In the dry valleys, October to February mean temperatures are -23.7 degrees to 0.7 degrees C. In December and January, temperatures fluctuate around freezing. There are large variations between years and between localities. In general, the summer temperatures for the inland ice-free areas exceed those along the coast; in winter, the situation is reversed.

Annual snow accumulation on Ross Island averages 17.6 centimeters (water equivalent). Accumulation over the ice plateau, west of the Dry Valleys, is considerably less, 3 to 10 grams per square centimeter. Within the Dry Valleys, most of the snowfall is associated with humid easterlies blowing off the Ross Sea.

Winds in the Dry Valleys range widely in direction and velocity and are controlled by the local topography, the proximity of the ice plateau and the ocean, and the season of the year. Onshore winds from the east dominate during summer with mean speeds of 10 to 15 kilometers per hour. During the winter, westerly katabatic (or gravity-driven) winds, originating on the ice plateau, sweep through the valleys.

The winter winds affect the orientations of ventifacts (stones shaped by the wind) and cause pebble ridges to form. In all of the Dry Valleys, ventifacts commonly are positioned with their cut and polished facets facing west. Pebble ridges with lee slopes facing east are particularly prominent in the upper Victoria and Barwick Valleys. Pebbles along the crests are as large as 6 centimeters in diameter. Velocities necessary to transport such large particles have been calculated to be 200 kilometers per hours.

WANT TO LEARN MORE?
Websites

 • McMurdo Dry Valleys Long-Term Ecological Research (LTER)
The homepage for the LTER project in the McMurdo Dry Valleys.
 • Virtual Tour - McMurdo Station, Antarctica
A virtual tour of McMurdo Station including images of British explorer Robert Falcon Scott's hut.
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