-40 and -40

McMurdo Sound, right about the time the temperature hit the record low so far for this year. The memorial visible on the hill is Vince's cross, George Vince was a seaman on Scott's first voyage to Antarctica.

It’s a cold one today at McMurdo, we just past the magic temperature of -40… the point where the Celsius and Fahrenheit temperature scales converge (briefly).  This is the temp without windchill, with the windchill it’s a brisk -59 C (-74 F).  I took a brief walk to snap this picture of the sunset and made the mistake of facing into the wind for a few seconds, the tears froze to my face instantly.  I wouldn’t want to be at the ice edge right now (it was much warmer when we were there on Monday), but I bet young sea ice and frost flowers are forming everywhere on the open water. 

We hear a lot about windchills and we’ve all experienced how much cooler it feels when the air is moving past us.  Many people misunderstand the term however.  It’s not that the air is any cooler when there’s wind around, we feel cooler because we’re losing heat so much faster.  This heat loss is what the body registers as temperature.  A piece of metal placed outside at -40 C with a windchill of -59 C will never get colder than -40 C, but it will reach that temperature much faster than on a still day. 

It’s been a warm, snowy year and as a result the sea ice around McMurdo Sound is warmer (and thinner) than usual.  Among other things this has being causing problems for travel over the ice; cracks and weak spots are continually appearing.  Today’s low temperatures, aided by the wind chill, should rapidly cool any exposed ice surface and have a noticeable impact on ice growth and ice strength. 

Update… I just got word that it bottomed out at -42 C, the coldest day of the year so far for McMurdo Station!

5047 Total Views 2 Views Today
This entry was posted in McMurdo 2011 field season. Bookmark the permalink.

One Response to -40 and -40

  1. fascinating… experiencing tears freezing like that seems like a fairly unique human experience.

Leave a Reply

Your email address will not be published. Required fields are marked *

WordPress Anti Spam by WP-SpamShield