Saharan dust layer clouds Cayman skies

Hazy conditions are forecast for Cayman through Thursday, as a plume of Saharan dust settles over the Caribbean region.

The Public Health Department is encouraging individuals with respiratory illnesses, such as asthma, to stay indoors as much as possible and to contact a healthcare professional if they experience any difficulties.

The dust layer is forecast to remain over Cayman for the next few days, according to the National Weather Service.

“While this phenomenon is typical at this time of the year, this plume of dust is observed to be denser than in previous occurrences,” the weather service said.

Researchers have described the current Saharan Air Layer as the most significant in decades.

In Puerto Rico, where a public health advisory was issued over air conditions, Dr. Olga Mayol of the Institute for Tropical Ecosystem Studies told media that the event had brought the highest concentration of dust particles observed in the region in 50 to 60 years.

By Wednesday, the dust forced the Mosquito Research and Control Unit to pause its aerial spraying, despite the increased mosquito population in Cayman.

“This is to prevent material released by MRCU planes binding to the dust and rendering that material much less efficient in controlling biting mosquitoes,” an MRCU release said.

“Truck spraying will continue as the material sprayed is released at ground level and therefore not impacted by dust in the upper atmosphere. Due to current weather conditions, the trucks are most effective to continue fighting the recent increase in mosquitoes.”

It advised the public that the current mosquito population is not disease-carrying. Aerial spraying was expected to continue after the dust plume had passed.

Hazard Management Cayman Islands explained in an online post that most of the dust during these events originates from dried-out portions of Lake Chad. Despite the negative impact on visibility, the dust provides needed nutrients to certain ecosystems.

“The Saharan dust is the single largest source of dust on planet earth and has a vital role in providing nutrients for plants, including in our own region. It also provides a significant source of nutrients for the marine environment,” the HMCI post read.

“The dust also has an important role in feeding the plants in the Amazon Rainforest and even the US wheat crop is supported by the dust, which contains important minerals such as iron which are vital for plant growth.”

Individuals with respiratory issues were encouraged by HMCI to contact Public Health.

“The extra particles in the atmosphere may contribute to beautiful sunsets,” HMCI wrote, “but the downside is that it can also cause air quality to worsen and some persons with allergies or respiratory illnesses may find they are somewhat affected by the dust during large plumes.”

MLA Alva Suckoo said that a meeting with Hazard Management on Tuesday had indicated the dust should have minimal impact on Cayman.

“However, this is an unprecedented event based on the size and there is some uncertainty,” Suckoo said in written message.

“Based on information coming out of Jamaica, some of the dust will be low lying, therefore, asthmatics and others with respiratory issues need to take precautions such as wearing masks when outside and staying indoors as much as possible.”

Suckoo said he anticipated the impact on Cayman to last about six days, with the intial surge coming Tuesday night and Wednesday morning.

The plume is forecast to continue westward, according to weather.com, and affect the US Gulf Coast by the weekend.

The Sahara dust air mass.

Despite the effect on air conditions, the Saharan Air Layer comes with a silver lining.

The dust plumes are associated with suppressed hurricane activity, in part due to the dryness of the air mass. They also can cause colourful sunsets. The US National Hurricane Center reported Tuesday that the dust had covered most of the Caribbean, and the dry, stable air was inhibiting convection in the region.

Saharan Air Layers typically start forming in mid-June and continue through mid-August.

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