What is a “Flash Drought” and Why Are They Becoming More Frequent?
It's crispy-crunchy-dry out there right now, and trending drier with every passing week. Most of Wisconsin is in moderate drought with pockets of severe drought showing up in both Wisconsin and Minnesota, according to the latest US Drought Monitor. With any luck heavy showers and thunderstorms will deposit an inch or two of rain on some lucky towns over the weekend, possibly taking the edge off a deepening drought. But it's not your imagination: droughts are coming on faster than they did a generation ago, a symptom of a warmer atmosphere.
Looking at the historical record droughts would usually build slowly, over the span of months and years. But in recent decades "Flash Droughts" have become more frequent and intense, worldwide. New research highlighted in the Journal Science concludes: "Flash droughts such as this are developing more quickly and happening more frequently because of climate change."
The authors of the new study discovered that these fickle and sudden flash droughts were 2–3 times more common in humid regions than in others, and they are showing up across most of the planet. These "instant-on" droughts are harder to predict and more difficult to prepare for. “We need to stop thinking of drought as a slowly developing disaster and start thinking about it as something that can happen really quickly" one of the co-authors wrote. Less precipitation, greater evaporation, and hotter days are driving the trends, according to the researchers involved.
Significant rainfall is possible this weekend, mainly over the northern half of Minnesota, where some 1-3" amounts are possible from numerous swarms of showers and T-storms. It may temporarily take the edge off our drought, but if history is any guide, an intensifying El Nino may serve to keep us warmer and drier in the weeks and months ahead.
Flash floods - flash droughts. Mother Nature has picked up her remote control and put our weather systems on fast forward, one more symptom of how a warming world is flavoring all weather now.
It's a brave new world out there. I'm going to need a bigger irrigation system...