Macquarie Island Adventure: The Deep Freeze

This post continues on from the previous two.
As mentioned in the last post The Fabulous Furious Fifties the weather systems zoom across Macquarie Island at a fast pace.

In the last week of July we experienced a sustained, very cold blast.
We are in the zone for extreme conditions. In saying this the temperatures on Macquarie island don't vary that much, because of the moderating effect of the surrounding ocean. On many days the 24 hour temperature variation is only in the order of 1°C to 2°C.

Looking south across Buckles Bay at the frozen landscape - a snow shower is moving in from the southwest

Though we do not experience the the profoundly cold temperatures that my colleagues on continental Antarctica experience, we occasionally receive a cold blast from the south.

This was the scene I encountered on leaving Hasselborough House (accommodation) on the morning of the 25th July

Just after sunrise on the 25th July - snow, wind and cold

View from the station on the morning of the 25th of July

For a couple of days from the 22nd of July a series of cold fronts crossed the island bringing with them the usual periods of rain, drizzle and showers. Then as the low pressure system that was associated with these fronts passed south of the island, another, significant cold front crossed Macca during the afternoon of the 24th.

After the front moved through the winds turned southwesterly bringing a cold blast. The air-mass had been transported all the way from the Antarctic continent.

View from the station across Buckles Bay (east coast) on the morning of the 25th - heavy snow had fallen overnight. Mt Elder looms in the background

Looking across Buckles Bay towards Gadgets Gully - Can you see the fighting elephant seal on the beach and the two rows (dark) of king penguins near the base of GG

View from station to the west to Handspike Point across Hasselborough Bay

Despite the moderating effect of the Southern Ocean waters the temperature dropped to way below freezing and produced frequent, heavy snow showers for the next 36 hours. The lowest temperature recorded in that period was -8.5°C (17°F) which wasn't far off the lowest ever recorded of -9.4°C (15°F).

The following pictures were taken from the station.

Yours Truly standing just outside the Weather office

From the isthmus - Three big elephant seals oblivious to the cold

Artefact enclosure next to the Green Store. They were frozen solid

Looking west across the 'Magnetic Quiet Zone'

Looking southwest from the top of fuel tanks - note the blowing, drifting snow

All official air temperature readings are taken from instruments inside a Stevenson Screen which is a white painted, slatted timber box mounted on a pole. This instrument shelter is oriented so that the door opens to the south. Does anyone like to comment on why it opens to the south? The instruments inside are at typical eye level of around 1.4 metres (~4.5 ft).

Stevenson Screen at Macquarie Island

Wind swept snow from the top of the fuel farm

Wide angle shot of the island to the south of the station (taken from the top of the fuel farm)

Snow blowing from the top of the escarpment (taken from the fuel farm)

We also take a temperature reading on the ground surface - terrestrial (ground) minimum temperature. Typically this is lower then the temperature measured in the Stevenson Screen. A terrestrial minimum of -11.0°C (12.2°F) was recorded on the 25th of July. This was just short of the all time record of -11.1°C (12.0°F). As you can surmise it was a very cold day on Macca.

The following pictures were taken while wandering around station limits.

From the lookout - Crepuscular rays breaking through the cloud just ahead of another heavy snow shower coming up from the southwest

From the lookout with a wide angle lens - looking down Razorback Ridge then across the isthmus to North Head

From the lookout - to the north - again note the snow blowing off the plateau

Near the bottom of the steps to the lookout - young elephant seal encrusted in snow and ice

Snow encrusted young elephant seal

During the cold outbreak it was also very windy which made for an extreme windchill. The strongest gust for the period was 67knots. When the temperature was at its coldest the wind was blowing at 35 knots gusting to 55 knots. The resultant windchill was between -20°C and -22°C (-4°F and -8°F). At the time I was just finishing work (1:30am) and it was a interesting walk from the weather office back to station.

The following were taken in the amazing varying light later in the afternoon of the 25th of July

Snow covered escarpment beautifully lit by the setting sun

Looking south across the 'magnetic quiet zone' with the late afternoon sun breaking through occasionally

Young elephant seal sheltering amongst the tussock

Young elephant seal encrusted in snow and ice

Large cumulus cloud coming across the escarpment, lit by the setting sun

Large cumulus cloud coming across the escarpment, lit by the setting sun - a heavy snow shower can be seen south of the Nuggets

The temperature of the waters around Macquarie Island are close to 4°C (39°F), so it was quite surprising for the air temperature to be so low. As a result, the sea water was freezing on the rocky outcrops around the coast.

Looking out over Garden Bay just behind Garden Cove and Cumpstons Cottage

Sea water frozen on the rocks in Garden Bay

As I was not able to be down island during this event, some of my fellow expeditioners (MIPEP and FTO) took some pictures, which i include below. Keep in mind that the temperatures would have been colder and the wind stronger up on the plateau.

Eitel (watertank) hut (photo by Leona Paislier - MIPEP)

Green Gorge hut about halfway down island on the east coast (photo by Marty Benavente - FTO)

Mt Hamilton in the distance with a frozen Tiobunga Lake on the right (photo by Marty Benavente - FTO)

Karen (MIPEP) on the plateau with hunting dogs Ash, Chase, Bail and Finn (photo by Leona Paislier - MIPEP)

Sandy Bay and Brothers Point - you can see the red Brothers Point hut at the bottom of the valley just above the coast (photo by Steve (Billy) Barton - MIPEP)