Shifting sands - stormy times around the world with dramatic consequences. by Susan Powell
Sand - the most concern many of us have to give it is perfecting the odd castle on the beach on hols, but when large volumes get on the move the outcome can be far more serious...
Every spring, for weeks at a time, northern China and the Korean peninsula fall under the cover of stinging yellow clouds.
These though are not clouds in the traditional sense, made of droplets of suspended water, but clouds of sand grains and industrial pollution particles. They initially originate from dust storms across China's Gobi desert but can then migrate hundreds of miles eastward on the wind.
Their intensity varies from year to year but their appearance is always guaranteed. This year the sands began hitting North Korea on March 17th - prompting immediate efforts to minimise damage to crops, livestock and people. Protective clothing, sunglasses and masks have become the traditional spring fashion here!
Tiny dust particles may not sound too much of a threat - but by the time the clouds cleared last year 4.1 tonnes of dust had been dumped per square mile over North Korea's capital Pyongyang alone. Clearing the aftermath has always proved costly to the economy but now scientists are also paying particular attention to the nation's health.
Meanwhile in the USA environmentalists are currently very concerned about the health of beaches around the Gulf of Mexico in the wake of last years Hurricane Ivan.
Ivan made landfall on September 16th 2004 at Gulf Shores, Alabama, with 115mph winds and a storm surge estimated at 3-4m (10-13 ft) high. The storm is estimated to have washed away as much as 50m (164ft) of beach in places.
The US Geological Survey, NASA and NOAA (National Oceanic and Atmospheric Administration) have been jointly measuring the damage done by hurricanes, such as Ivan, in recent years in terms of land and sand loss. Much of the surveying to date has been done with an airplane equipped with 'lidar', which is similar to radar but uses laser light in place of radar's radio waves to map surface contours.
The findings were presented a the National Hurricane Conference in New Orleans on Friday by Abby Sallenger, an oceanographer for the Geological Survey's Centre for Coastal and Watershed Studies in St Petersburg, Florida.
Ivan was the worst hurricane of the 2004 Atlantic hurricane season and strongly served to illustrate how vulnerable the US is to large scale destruction by storms. The erosion caused by Ivan's waves and storm surge toppled five-story seafront condominium buildings - the largest buildings to fall during US hurricane history!
Sallenger stated the average shoreline erosion was 13m (42ft) in the area where Ivan came ashore, roughly between Alabama's Mobile Bay and Pensacola Bay in Florida.
Some of the sand is expected to reappear on beaches and barrier islands, but Sallenger said sand swept into inland bays and onto shore will not be returned by natural processes.
Just goes to show - sand is definitely not something to be taken for granted when out with the bucket and spade!
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