Unsettling times for our climate
What on earth has happened to our spring, for heaven’s sake? Plainly, your experience of the season so far will vary, depending on what part of the country you live in, but that might well be a question that has been on the lips of many, in a range of locations.
The answer, it seems, may be a slightly qualified ‘‘not as much as you think’’.
The word ‘‘unsettled’’ has been widely used. Unusually high November rainfall has hit some parts of the country, with lower than normal temperatures, and hail has been widespread, from the lower South Island, where it made some stretches of road look like they had been snowed on, to the lower reaches of the North
Island. It hailed in our capital yesterday afternoon. A couple of weather systems bringing actual snow down to low levels in mid-November have possibly been the most surprising occurrences.
On Sunday afternoon, there were widespread reports, accompanied by some dramatic video footage, of a tornado hitting farming country north of Ashburton. There was some debate about whether or not the dramatic funnel formation stretching earthwards from heavy cloud was actually a tornado, or a large ‘‘dust devil’’, but meteorological opinion seems to have settled conclusively on the former. Certainly the thunderstorm activity that is required for a tornado to develop was present.
All of that makes our weather sound fairly unsettled, so it might be surprising to hear the analysis from Metservice duty meteorologist Tui McInnes yesterday that the most unusual weather
feature of the spring so far was actually the highpressure system that produced settled weather for much of the country last week.
Low-pressure systems, and thus fairly unsettled weather, are typical for spring, he said.
What had been ‘‘quite unusual’’ was the snow down to about 400 metres above sea level, and even lower in some areas. It was ‘‘not unheard of’’, but not common. ‘‘The cold temperatures are the most unusual [aspect of the spring weather].’’
Naturally, and especially coming so soon after a major report released by the Intergovernmental Panel on Climate Change (IPCC), our spring weather has prompted debate about climate change. We’ve been told more extreme weather events, particularly flooding and drought, are to be expected. Which is why the need to limit the increase in global temperatures is so urgent.
But in the wake of Sunday’s Mid Canterbury event, McInnes says the country is not seeing an increase in the frequency of tornadoes, which still represent a ‘‘small-scale phenomenon’’ in New Zealand. Factors such as population increases and the ease of communications – such as the ability of people to take video footage and share it on social media, meaning news of them spread further – outweighed ‘‘anything else measurable’’ with regards to tornado activity, he said. So there’s no need to rush off and build a tornado bunker.
Forecasts indicate temperatures may return to more normal levels by next week, as the onset of summer approaches. Of course, this is all rather short-term, so while some relief from unsettled weather conditions may be ahead, our long-term climate challenges haven’t changed.
‘‘The most unusual weather feature of the spring so far was actually the high-pressure system that produced settled weather for much of the country last week.’’