Australia (Commonwealth Union) – Intense short-duration rainfall occurrences in Sydney have been increasing to new levels, raised by 40% in the last 20 years, according to a new study. The results, published in Science, indicate that sub-hourly rainfall extremes could be increasing more rapidly than previously assumed.
Rapid rain bursts, are the most intense and damaging of downpours. As this occurs, a large amount of water falls rapidly over a small region, potentially overwhelming roads, gutters and drainage systems in a short duration of 10 minutes.
Climate scientists have found it difficult to note trends in this extreme weather phenomenon because of restrictions with rain gauges, satellite data and climate models in detecting small-scale storms on prior occasions. The new method gave researchers from the Australian Research Council (ARC) Centre of Excellence for Climate Extremes the capability to identify 1000s of rapid rain bursts across Sydney over the last 2 decades.
“If this trend continues in Sydney, the city needs to be more prepared for rapid rain bursts and flash flooding into the future,” said Professor Jason Evans, a co-author of the study at The University of New South Wales. “This should factor into our city planning with buildings, roads and communities needing to prepare for the likelihood of more rapid rain bursts to test the short-term capacity of our drainage, roads and flood plains.”
Prior research of climate effects on extreme precipitation had attention primarily on daily rain totals. However, hourly extremes regularly get generated in small areas possibly missed by gauge networks or satellites, and unaccounted for in climate models. Researchers indicate more studies will be important to equip cities globally for the elevated possibility of increased rapid rain bursts in the future. Even places having little trend in rainfall extremes daily, elevated risks of flash flooding if the intensification of sub-hourly rainfall extremes continuing is a possibility.
