At Macquarie Island, a walking track is given an update and BOM meteorologist Barry Becker provides details on the first winter blast.

Track work with Chris

I’ve been out and about a fair bit in recent times undertaking repairs to some of the walking tracks on the island. Whenever possible, walking around the sensitive landscape of Macca is confined to the walking tracks. Walking tracks are usually confined to harder rocky terrain, but often tracks will cross more sensitive areas.

Occasionally, repairs are required to be undertaken in order to repair damage or limit further damage occurring. Over the last year or two, stockpiles of timber decking have been flown into different locations by helicopter during the island’s summer resupply. The sites selected have been identified by previous rangers as being sensitive and prone to damage by foot traffic. Progressively, the works program has migrated to each of these locations and narrow sections of the double plank walkway have been constructed. 

Completing some of these remediation works before the onset of winter will ensure that nature’s regenerative power will kick in as the weather warms up in the coming spring. The vegetation on Macca is really starting to show signs of regeneration with the removal of rabbits. 

People are always looking for a chance to get off station or vary their tasks a little for the day and I’m always glad of a helping hand and a bit of company. Aaron wrote a story about helping out just recently titled 'ranger step aerobics’

Working on the Island Lake track, FTO Marty dropped in for a few hours and lent a hand with the laying of timber decking. Karen and Nick from the MIPEP team also dropped by to help for the day — a welcome change to their routine after scouring the landscape for any sign of rabbits. Nick particularly enjoyed swinging the sledge, relishing the chance to do a proper bit of physical work. The hunting dogs took the moment to have a well earned break.

First winter blast

On Saturday night into Sunday morning we had our first big snowfall for this season.

It came about as low pressure system that passed over the island on Saturday and as it moved east it was followed by a colder southwest to southeast flow on Saturday night and through Sunday. This can be seen on the first three mean sea level pressure analysis charts shown below. Note that winds or flow is clockwise around a low and anticlockwise around a high.

We woke on Sunday to find snow had settled at the station and the slopes. Marty, Patty and Steve left station early Sunday for field training. Aaron and I took the opportunity of walking the loop track. It was stunning to see the countryside covered in snow. 

On Sunday night into Monday morning, the southwest to southerly flow over the island brought colder air from the deep southern waters near the Antarctic continent, shown on the next three charts. The result was frequent snow showers and blowing snow throughout Monday, with the temperature hovering between −4°C and −2°C all day, only managing to peak at a maximum of −1.4°C. This was not far off the coldest May day of −1.7°C.

Spare a thought for the wildlife as the ground temperature hovered around −5°C with the minimum ground temp of −7.1°C recorded.

The ‘cold pool’ of air moved northeast in the strong southwest flow and hit New Zealand with a cold, snowy blast on Tuesday, with heavy snow and cold temperatures recorded all over, including much of the north island.

By Tuesday morning the Macca weather returned to normal: a balmy 5°C.

Barend (Barry) Becker