Just wild weather or climate disruption?
A record heat wave across southeastern Australia, flash floods in Queensland and evacuations in California, Chicago thawing after being frozen stiff by a sudden icy "arctic vortex": Just normal, or out of the ordinary?
'Rossby waves' unlock weather puzzle?
"Breakthrough" insights into atmospheric dynamics are emerging from "high-maths" —scrutiny of satellite data, say scientists. Their Nature magazine article identifies "significant connections" between extreme rain events, often far apart. Their premise: global rainfall distribution stems "probably" from planetary waves named after the late Swedish-born American meteorologist Carl-Gustaf Rossby.
Deluged in Townsville, Queensland
Normally, monsoon rains over northern Queensland last a "few days," says Australia's Bureau of Meteorology. Unprecedented downpours began a week ago, with more forecast and troops sent to a disaster zone. Evacuations have included these residents of Rossela, near Townsville, and German and Swiss tourists plucked from the Diamantina River catchment by a local farmer using his private helicopter.
Tasmania scorched, wildfires
Wildfires have scorched swaths of Tasmania, offshore from continental Australia's Victoria state, where residents last month faced a record heat wave. Australia's Bureau of Meteorology (BoM) blames the trend partly on record-warm southern Tasman Sea temperatures that have blocked rain-bearing cold weather fronts. These flow normally west-to-east under Australia toward New Zealand.
Denuded California braces for Pacific storm
Its hills denuded by recent drought-induced wildfires, California's central coast braced Saturday for another Pacific storm, with heavy rainfalls forecast. Santa Barbara County ordered evacuations from areas still clogged by past fire debris. Avalanche warnings were in place on the Sierra Nevada, loaded with snow from storms in January.
Chicago thawing
The US Midwest, including Chicago, is thawing after a sudden two-day arctic vortex chill. At least 18 people died. Normally, the icy air mass swirling over the darkened North Pole during the winter stays ringed by the polar jet stream at about 60 degrees north. Stream weakening was also behind the prolonged 2018 European summer drought, according to Potsdam's PIK climate institute.
Monsoon rains, Indonesia
Indonesia, like much of Asia, weathers annual monsoon rains. Last Tuesday, the Sulawesi islands counted its toll: at least 70 people were killed as rivers burst their banks and landslides buried village homes. Authorities said a state of emergency would remain in place until February 6.
Recent extreme heat waves and floods have scientists wondering if jet streams are weakening and larger-scale atmospheric "Rossby" waves are changing. The magazine Nature says high-end mathematics applied to satellite data by researchers has revealed "concise links" between non-tropical rainfall events in Asia, Europe and North America, sometimes over thousands of kilometers.