x Abu Dhabi, UAESunday 23 July 2017

Rare rains pay visit to eastern mountains

Process aids natural cloud formation and helps raindrops form, although experts disagree on how effective it actually is.

ABU DHABI // As the midsummer sun baked the rest of the UAE, in the mountainous region to the east, raindrops fell. The clouds that billowed up were stoked by normal weather conditions, according to Dubai International Airport's meteorological office. But the droplets that eventually fell this week may have been prodded to life by a cloud-seeding mission launched from Al Ain.

"I couldn't believe it was summertime and it was raining," said Phillipa Barlow, the manager of Al Awadi Stables near Dhaid. "We had a couple of drops of rain and then massive, massive thunderstorms and lightning." "It was like January," she added, noting that the electricity failed for nearly four hours. "Very, very angry skies." More than 4mm of rainfall splashed down into the Manama area, helping to top off reservoirs and wadis, and offering a respite from the heat to the southern parts of Hatta, Dhaid, Meleiha, Felli and Madam. Much of that water feeds into drinking systems.

"This [water ] needs to be replenished," a spokesman from the meteorlogical office said. "They're trying to enhance the activity with cloud seeding." While much of the UAE is seared dry during the summer, the eastern parts of the country see occasional rain as moist air is driven upwards by mountains. That makes the region more suitable for cloud seeding, experts say. The National Centre of Meteorology and Seismology has been seeding clouds since 2001. The practice has been criticised - it is difficult to gauge its effectiveness, and sometimes it has been blamed for creating catastrophic storms - but it is used worldwide, including in the US and Britain.

A spokesman from the centre said the current seeding programme would continue until September. A separate one runs from March to June. The process involves using sounding rockets or aircraft to spray tiny particles of sodium chloride, calcium chloride or silver iodide into the air, around which water droplets are supposed to form. When enough large droplets coalesce, a cloud begins raining. But the seedings are ineffective when the proper weather conditions do not prevail, experts say. To have any effect, the atmosphere must be unstable, producing well-developed clouds with a high concentration of moisture - the scenario during the past week around Manama.

In the UAE, twin-engined King Air C90 aircraft are used to spray clouds at altitudes of 3,000 to 4,200 metres. In the Emirates, cloud seeding was first done in collaboration with the US-based National Center for Atmospheric Research. Internationally, the first experiments with cloud seeding began in 1946, when the process was used to encourage snowfall in the US. China is one of the world's biggest practitioners, using rockets to launch particles of silver iodide into cloud layers.

dbardsley@thenational.ae * Additional reporting by Anna Zacharias