By Dapo Akinrefon
TOWARDS the end of every year, the nation is besieged with a different kind of weather. The weather, which comes during the Yuletide season usually comes with it excitement in the air.
Known as the harmattan, it comes with its own aura and many prefer it to the cold and hot weather.
Though most people opine that the harmattan is a season that occurs each year but indeed, the harmattan is a hot, dry and dusty wind (continental trade wind) blowing over West Africa.
This northeasterly wind blows from the Sahara Desert into the Gulf of Guinea between the end of November and the middle of March (winter). The name comes from or is related to an Akan cognate.
On its passage over the desert, it picks up fine dust and sand particles (between 0.5 and 10 micrometres). The air is particularly dry and desiccating when the Harmattan blows over the region. At morning, low temperatures can easily be as low as 15 °C (59 °F) or 20 °C (68 °F). At afternoon, high temperatures easily soar to more than 30 °C (86°F) and can reach as high as 40 °C (104 °F) sometimes, while the relative humidity drops under 10%.
According to weather experts, the Harmattan blows during the dry season which occurs during the lowest-sun months, when a high pressure system of the subtropical ridge stays over the central Sahara Desert and when a low pressure system of the Intertropical Convergence Zone (ITCZ) stays over the Gulf of Guinea.
Expectedly, the Harmattan brings desert-like weather conditions which lowers the humidity, dissipates cloud cover, prevents rainfall formation and sometimes creates big clouds of dust or sand which can even result in violent duststorms or sandstorms but when the haze effect is weak, this dry wind creates beautiful sunny days with plenty of clear skies.
With the haze hitting parts of the country especially Lagos State, it is expected that the harmattan will come with mixed feeling.
Perhaps, one of the disadvantages of this dry weather is disruption of flight operations in the country, especially from Lagos.
It is, however, expected that the harmattan, perhaps, will result in some major airlines diverting their flights.
Due to the dry weather, the possibility of fire outbreaks is usually high at this time of the year.
Fire outbreaks usually have high records during this period.
Also, as the dryness in the atmosphere increases, people are prone to be infected with various airborne diseases.
In 2013, Nigerian Meteorological Agency (NIMET) warned of adverse weather in most parts of the country owing to the harmattan haze.
Besides this, conditions are expected to cause some levels of discomfort as heat-related ailments were expected to be prevalent in the areas during the hot season.
While air-borne diseases usually triggered by Harmattan dust haze are also likely to be prevalent in most parts of the country, the prospect of cold weather-related diseases such as pneumonia, catarrh and cough are likely.
As the harmattan berths in Lagos, it would be imperative for health practitioners and governments in states like Lagos to make contingency plans in the event of outbreak of diseases.