The Nigerian Civil Aviation Authority (NCAA) has issued a weather alert to all pilots indicating hazards associated with harmattan dust haze during flight operations at this period of the year.

“This warning is important as Harmattan is known to pose an obvious threat to aircraft particularly in areas of challenging terrains due to low visibility.

“This alert is in line with the Seasonal Rainfall Prediction issued by the Nigerian Meteorological Agency (NIMET) on the cessation of rainy season in 2014”, the warning, issued in a press statement by the General Manager, Public Affairs, Fan Ndubuoke said.

The Harmattan is a dry and dusty wind that blows southwards from the Sahara across the country between the end of November to March, the following year.

On its passage over the desert, it picks up large amount of fine dust particles (0.5 to 10 micrometers) which are transported hundreds of kilometres over the south.

The effect of the dust and sand stirred by the wind is known as Harmattan Dust Haze.

In addition, the warning notice adds that “the consequence of the Harmattan is a heavy fog, hence air – to – ground visibility is considerably reduced.

“Aerodrome visibility may fall below the prescribed minims and in severe conditions; dust haze can blot out runways, the markers and airfield lightnings over wide areas. This makes visual navigation extremely difficult or impossible.

“Where visibility falls below the prescribed weather minims, flight operations are likely to be delayed, diverted or outrightly cancelled.

“Therefore, all Pilots shall obtain adequate departure, en route and destination weather information and briefing from NIMET prior to flight operations at all the airports.

“Pilots are similarly advised to exercise maximum restraint when strong surface wind, fog or Harmattan haze is observed or forecast.

“All concerned are required to ensure compliance with this circular”, he said.