The islands have been hit with poor visibility as a result of Saharan dust.

Poor visibility was reported in the Canary Islands on Wednesday as a dust-laden wind swept in from the east.

This local wind is known as a Calima, and it is particularly prevalent in the winter and early spring months. Very similar to the more widely known Scirocco, the Calima is associated with disturbed weather over the Sahara desert.

It usually blows from the southeast or east and the dust passes over the islands, resulting in poor visibility. The dust itself may continue blowing across the Atlantic before eventually being deposited in the Caribbean, or even the United States.

This Calima was a weak affair. Sunshine turned hazy across the island chain, but there were no problems reported.

At its worst, the Calima can severely reduce visibility. On one occasion in January 2002, the international airport at Santa Cruz had to be closed as visibility dropped below 50 metres.

Fortunately the lowest reported visibility this time was 1,300 metres at Tenerife and 2,000 metres at La Gomera.

Vast amounts of dust are currently on the move across North Africa, with low-pressure systems drawing surface mineral dust high into the atmosphere.

Dust storms are already being experienced in Egypt, Sudan, Chad, Niger, Syria and Iraq. Over the weekend the dust will spread across Saudi Arabia and Qatar.

It is possible the region may experience some flight disruptions, partly because of poor visibility, and partly because of concerns about the effects of large amounts of dust being drawn into aircraft engines.

Many people experience respiratory problems in these dusty climes and it is likely that the situation will be much worse over the next few days.