A day for the records

Sunday the 18^th saw some rare and amazing weather lash Casey station. Poorly timed during resupply, we have been in the path of an intense low pressure system for several days. It has brought with it gale force winds that left the station in standby mode for a couple of days. Many of us saw our first blizzard on Sunday with the blowing snow reducing visibility to about 20 metres. The winds we experienced had the weather crew dusting off their record books. At 07:29 we experienced a wind gust of 109 knots (202 km/hr) which eclipsed our previous December record of 181km/hr in 1995. On Tuesday the 20^th the same weather system gave us a December low pressure record at station of 940.2hPa just to prove what a beast it really was.

However, the most amazing event that the system brought with it was a thunderstorm at 8am on the Sunday. Thunderstorms are a common site on mainland Australia but very rare in Antarctica. This is because they generally need warm moist air combined with an unstable atmosphere to provide the necessary convective uplift required for cumulonimbus clouds to form. These are the clouds that give us thunderstorms. Being the coldest, driest continent on earth it’s not surprising that they are very rarely seen down here.

The duty observer was performing his morning weather observations noticing that the sky was looking rather evil. He never expected what would follow though with a lightning strike touching down about 1km away. A loud crack of thunder resulted and the show was completed with a cloud to cloud lightning strike. These set off two fire alarms which meant that all on station had to muster, a tough ask at 8am on a Sunday morning! When the observer notified the fire team that the alarms were due to lightning the common response was ‘we don’t get lightning down here!’. Thunderstruck was promptly played over the station radio with the local weather enthusiasts very excited about what had eventuated.