The town of Mildura in northwest Victoria, Australia, was enveloped in a huge dust storm at about 5.00 pm local time on Tuesday 7 May 2019, reducing visibility to almost zero within a few minutes. This is thought to be the largest such storm to hit the town in about 40 years, and is a highly unusual event at this time of year, with dust storms common in northwest Victoria in spring and summer (September to February) but generally suppressed in autumn and winter (March-August) by higher rainfall. However, the southeast Australia has been suffering a draught this year, and while this has now broken in some areas, rains have yet to reach the westernmost parts of Victoria as well as South Australia.
Dust storm sweeping over the town of Mildura, Victoria, on 7 May 2019. ABC.
Most of Australia has an arid or semi-arid climate, and the continent has always been prone to dust storms. However, Human activities are thought to have made these storms more frequent an severe, particularly since the arrival of European settlers on the continent in the eighteenth and nineteenth centuries, which led to the introduction of agricultural practises that proved to be unsustainable in the Australian climate, particularly intensive Wheat farming and Sheep raising. These led to the 'Australian Dust Bowl' period of 1895-1945, during which large areas of topsoil were lost, severe dust storms hit coastal cities such as Sydney and Melbourne, and farmers reported entire flocks of Sheep being wiped out by storms. Since this time steps have been taken to better manage farming practises in Australia, leading to a drop in dust storm activity, but concerns are now being raised that a warming climate is leading to longer, driest summers, and that dust storms are becoming more common again.
Dust storm sweeping over the town of Mildura, Victoria, on 7 May 2019. 9News.
As well as the obvious dangers associated with poor visibility, dust storms can cause (sometimes severe) respiratory problems, particularly for vulnerable groups such as children, the elderly, and people with pre-existing respiratory problems. The dangers associated with such storms depend very much on the size of the particles involved, with larger particles involved (sand) seldom making it past the nasal cavities, where they are unpleasant but not life-threatening, but finer particles (dust) often penetrating to the lungs, where they can be difficult or impossible for the body to deal with. This is particularly true of particles of silicate rock (such as quartz or chert) which the body can neither break down nor expel, with extreme or repeated exposure leading to silicosis, in which repeated, but unsuccessful, attacks on the foreign material by the immune system lead to areas of the lung becoming hardened and non-functional, which has a severe impact on health and is often fatal.
See also...
Follow Sciency Thoughts on Facebook.
