A pair of so-called "thundersnow" storms swept through parts of New South Wales and Victoria on Sunday and early Monday, August 6 and 7, 2017. The storms were a part of a snowstorm dubbed "Blizzard of Oz" that lasted 5 days.
Thunderstorm storms have been the centerpiece of a snow spectacular across the continent’s south-east. A series of polar lows have brought blizzards to higher ground with the white stuff even falling in the NSW Central Tablelands, far from the ski resorts, news.com.au reports.
"We had two bands of thundersnow hitting the Victorian and NSW Alps on Sunday, one during the afternoon and another one overnight," Sky News Weather meteorologist Tristan Myers told news.com.au. "Half a meter to a meter [1.6 - 3.3 feet] of snow fell across the Alpine resorts over the weekend, coupled with blizzards where winds gusted above 130 km/h [80.8 mph] at Thredbo. Although winds were fierce, we still got the best snowfall we’ve seen this season," he said.
In total, the snowstorm lasted five days and was dubbed Blizzard of Oz on social media. "It left behind some of the best snow accumulation the ski resorts have seen in years," WeatherZone's Ben Domensino writes.
A rare avalanche advice was issued by Vic Emergency on Monday evening following avalanches in the state's alpine region. The advice was reissued at 14:05 local time Tuesday, August 8 with reports that more avalanches had occurred on Tuesday morning.
"Avalanches are rare in Australia as the conditions which cause them aren't common in our alps," Domensino explains. "The recent spate of avalanches - which have mostly occurred in the back country away from patrolled resort areas - were likely the result of a unique sequence of weather events that occurred during the past week."
According to the UK Met Office, thunderstorms develop when warm air under colder air wants to rise. Generally, these conditions are much more common in summer and so it is not unusual to have regular thunderstorms throughout the summer months. However, they can also occur in winter as well.
If the weather is cold the rain associated with a thunderstorm can then fall as snow and thus is called thundersnow. This is unusual only because it can only occur in a few months of the year.
Interestingly, the snow contained within the thunderstorm acts to dampen the sound of the thunder. While the thunder from a typical thunderstorm might be heard many miles away, the thunder during a thundersnow event will only be heard if you are within 3.2 - 4.8 km (2 to 3 miles) of the lightning.
When thundersnow occurs at night the lightning seems brighter - this is because the lightning reflects off the snowflakes.
Featured image credit: BOM Victoria