Antarctica Sea Ice McMurdo Sound

Before too much time passes, I want to wrap up sharing about my 2020 Sea Ice work in Antarctica. In my last post about Antarctica, I introduced the idea of the sea ice and outlined a few highlights of early season sea ice work.  In this post I’d like to talk more about late season sea ice work and some of the science that takes place on the sea ice.

Small ice berg (Bergy bit) in McMurdo Sound

Sea Ice Formation (another quick overview):

The sea ice forms during winter in McMurdo Sound and the Ross sea.  Generally, the ice continues to grow through October, often becoming multiple meters thick.  As the Antarctica summer begins to set in, temperatures are consistently above 0 degrees and the sun is out 24/7.  The constant sun and higher sun angle have a very strong warming effect on the sea ice.  Generally, by December the sea ice has begun to warm to temperatures closer to liquid water (i.e. it is not ice).  Warming temperatures, cracks and swells contribute to breakouts of the sea ice.


During most seasons the sea ice breaks apart in January.  However, this isn’t actually a natural process.  It’s enhanced by human generated activity.  January is when McMurdo station prepares for a resupply vessel. Part of these preparations involve an ice breaker boat cutting a channel through the ice to clear a path for a Cargo Vessel and a Tanker bringing fuel.  The channel cut by the ice breaker begins to break the sea ice apart and often facilitates a large break away event.


Natalie setting up a temperature monitoring station (photo by Kirah Soloman)

My Role as Sea Ice Point of Contact (POC):

My job is to help the scientists who have research sites on the sea ice.  In a typical season we will have many different scientist groups at various research locations all along the sea ice.  Some groups will head out daily along well flagged routes (built by me), others will be navigating in un-flagged areas all over the ice gathering data.   It’s my job to manage and support all of these groups.


To do this I need to evaluate the sea ice throughout the season for stability, routes of safe passage and risk factors.  Typical risk factors include the appearance and movement of tension cracks on the ice.  I briefly discussed this in my previous post.  Cracking happens a lot in the early season and usually stabilizes until long after we are done working on the sea ice.  Other risk factors can include:

  • Glacier calving events

  • Cornice collapses

  • Ice edge work

  • Large break away events

  • White outs from rapidly changing weather

Large Glacier face in Antarctica

Erebus glacier Tongue

Sea Ice Science:

The range of science research on the sea ice can be quite diverse.  Most of it tends to be within the realm of biology (not ice science).   Some scientists study what is on top of the sea ice, Emperor and Adele penguins, Weddell seals, etc.  A few examples of research include long term populations studies, or researching how certain animals navigate (it’s almost like they have an internal GPS).


Other science research takes place below the sea ice in the water.  This can include population studies of specific animals like the Antarctica tooth fish, or the unique adaptation methods  certain species have gained to cope with the cold (like antifreeze in their blood).   There’s also research into the effects of water temperature rise on species.   The National Science Foundation (“NSF”) has a team of divers that help support much of this research.

Emperor Penguins

Not everything is biology based, and my above list of research is just a small sampling of the types of research you might expect.  However, some research would surprise you.  For example, there is one group of scientists for NASA who are working on the technology for piloting underwater robots in preparation for landing on Europa!  So freaking cool! (You can learn more about Antarctica science HERE>>)


Sadly, we only had one science group in 2020 on the sea ice, due to constraints of working around COVID precautions. This was a group studying the Weddell seal population.  They are based out of the university of Montana and have been gathering data for 50+ years.  It’s really great they were able to continue this process and not miss a full year’s worth of vital information.


The good news for me is that I was able to spend at least 1 day a week working directly with this group to help support them with their data collection.   I love being able to work more intimately with the scientists.  After all, supporting science is what all of us are there for.  I always learn a ton, and I got to spend a lot of time around the adorable seals!

Weddell Seal Pup (taken with NMFS Permit 21158)



Two Unique variables for This Years Sea Ice:

I went into 2020’s sea ice season with a few unique variables to consider.  One was the proximity of the ice edge.  The second was that we did not get an icebreaker or any resupply vessel (due to logistics around COVID).  In short, the sea ice seemed more likely to break away quickly (close edge) on the other hand it was unclear if it would break away fully at all (without an icebreaker).  Which made for a lot of unknown variables going into the season.


The proximity of open water to McMurdo is generally 14ish miles away.  Strong winds from the south consistently blow away ice creating a year-round polynya (a stretch of open water surrounded by ice). In fact, this is part of why we have some large emperor penguin colonies in this region of Antarctica (something discussed in the movie March of the Penguins).

satellite image of ice edge in relation to McMurdo Station

In 2020 the sea ice was only 7 miles from the station!  This was due to a spring storm and break away event back in late August and September.   Having a closer ice edge created a host of logistical challenges as well as an underlying concern about how long the sea ice would stick around.   No one in McMurdo had ever seen the sea ice edge so close, including the NSF station manager and the head diver who both have been going down for 40 years!


While I had hunches about how the sea ice might behave, I had no precedent or historical data to pull from and be sure.


What happened on the Sea Ice?:

For the first month and a half the sea ice behaved exactly as it had in previous seasons.   The ice edge did not move closer to McMurdo and the sea ice showed signs of being relatively stable.


Then we hit our summer season and the temperatures got above 20° F consistently the sun was high in the sky 24/7 and things warmed up.  After a few weeks of these warmer temperatures new cracks began to appear in the sea ice.   This, in and of itself, is typical of a warming cycle.   What wasn’t was the location of these cracks (not the normal spots) and the rapid growth.  By the end of November, I had multiple sea ice cracks that had grown several feet.  A few had grown over a meter wide and were still expanding outwards into the sound.

a large crack by Turtle Rock and a weddell seal colony

This type of accelerated growth is something that previously has only been seen in late season sea ice (January-March).    I was left with the challenge of re-routing roads to make safe passage for scientists and pondering what these rapid changes meant.   By early December, it was clear that all activity on the sea ice needed to get wrapped up quickly.  This made for some very long days.  Thankfully, the scientists had a successful season and all human generated equipment was removed from the sea ice without incident.

Natalie measuring crack growth (top picture is one week after lower)

While the sea ice didn’t break away that next week or even for many weeks- it did ultimately break out.   So, as to the question of if the ice breaker is necessary to generate large breakouts…we now have one data point that says- not always!

Weddell Seal scientist with Natalie navigating tricky multi year sea ice

I’m just grateful to have had as great of a season on the ice as we did- and that none of my scientists floated away!! It can be hard to make the decision of when to stop, or in essence turn around.   Yet, this is what I’m hired for.   Good decisions making is truly the foundation to any outdoor job and goes to the core value of risk management.



photos of seals taken with (NMFS Permit 21158)

Catalunya Permitir? A Quienes Den Positivo En Un Test De Ant?Genos Notificarlo En La Farmacia ajanta italia cierra todos los comercios, excepto farmacias y tiendas de alimentaci?n

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