As a thick haze shrouded Israel’s buildings and roads for the third day in a row on Thursday, scientists continued to ponder the equally hazy meteorological explanation for the dust storm, the strongest and most polluting such event to hit the country in 15 years.
The dusty conditions are the result of sandstorms raging in the Syrian desert.
However, why and how these sandstorms began at this time of year – and ultimately blew south to Israel and its neighbors – has puzzled meteorologists.
There have been no reports of such significant haze in early September since the country began recording weather measurements 75 years ago, Dr. Amos Porat, head of the Israel Meteorological Service’s Climate Department, explained on Tuesday, the first day of the event.
The sandstorms, which he described as “unprecedented for this time of year,” flowed into the region by northeasterly winds at a low altitude.
Dust storms in Israel are more typical in the winter and spring.
Dust levels have been so thick that the Environmental Protection and Health ministries have issued ongoing warnings advising that people with pulmonary or cardiac conditions – as well as the elderly, pregnant women, and children – stay indoors and refrain from physical activity.
As of Wednesday, about 600 people had been treated in hospitals as a result of the storm.
Although much lower than those measured on Tuesday, dust particle levels were in some places still up to five times the Environment Ministry’s “warning values” on Thursday evening.
Sweltering temperatures around the country, as well as mugginess in certain areas, have accompanied the dusty conditions. Both Arkia and Israir Airlines canceled all flights to and from Eilat on Tuesday and Wednesday, resuming them but rerouting their paths to the nearby Israel Air Force field at Uvda only at 2 p.m. on Thursday.
While the meteorologists know that the conditions blew in from the “exceptional sandstorms in Syria,” Porat said on Wednesday that the cause of these sandstorms still remains unclear. Although some weather activity and strong winds accompanied those storms, they were not on a scale that could account for what ensued, he continued.
Dr. Eran Brokovich, scientific director at the Israel Society of Ecology and Environmental Sciences, stressed that while many assumptions can be made as to the reasons behind the storm, such hypotheses require intensive scientific substantiation and cannot be immediately verified, despite the hopes of a public and media eager to know why the sand storm is occurring.
“You cannot come to scientists and tell them, ‘We want answers and we want them now,’ because you can’t always check things at that particular moment,” Brokovich told The Jerusalem Post on Thursday.
Questions remain regarding both the climatic system that caused the winds to blow this way, as well as the source of the fine-grained dust itself, Brokovich said. Such verification requires both climatic models that can be studied from afar, as well as actual examinations of the Earth at its source, he explained.
“Maybe it’s a one-time event of a certain kind of wind, and the dust was always there, but maybe we get these kind of winds often without the dust, and the dust itself is a new thing,” Brokovich said. “These are things we need to check and verify in a scientific way.”
Although Israeli scientists can work on climatic models to determine the reasons for the winds, they would face difficulties accessing the Syrian soil to examine the source of the dust itself, he added.
Some theories concerning the source of the dust involve the state of agricultural land in Syria, much of which has not been watered for a long time due to the flight of refugees.
Many of the fields could have become very dry and dusty as a result, but Israeli scientists cannot check this hypothesis, he cautioned.
Another theory involves climate change and the larger global desertification process, which “drives the creation of dust,” he added.
A third theory involves human activity and people’s influence upon natural habitats through activities like agriculture, he continued. If a desert is left alone, a crust forms on top of the soil that keeps it in place, preventing erosion and keeping dust at bay, Brokovich said. When people or animals or crops crush this thin crust, the possibility that more dust will be formed arises, he explained.
Although all of these options “may create an area that has a potential for a dust storm,” Brokovich stressed the importance of providing researchers with both the means and time to solve such issues.
“Scientists need the time to verify these educated guesses,” he said.
Whatever the precise reason for the storm, by Thursday evening dust levels still remained abnormally high. On a typical non-stormy day, levels of PM10 – particulate matter with a diameter of 10 microns or less – are at around 60 micrograms per cubic meter, according to the Environmental Protection Ministry.
As of 7 p.m. on Thursday, 24-hour averages of PM10 levels were generally highest in the Shfela region, the Jezreel Valley, Eilat and Jerusalem, ministry data said that evening. Shfela, Modi’in, Beit Shemesh and Rehovot showed 24-hour averages of 1,520, 1,500 and 1,200 micrograms per cubic meter respectively – figures that were 5.1, 5 and 4 times the ministry’s “warning values” and up to 25 times typical daily values.
PM10 averages in the Jezreel Valley were likewise 1,500 micrograms per cubic meter, five times the warning values, while those in Eilat and Jerusalem were 1,350 and 1,300 micrograms per cubic meter respectively – or 4.5 and 4.3 times the ministry’s warning values.
Levels in Haifa and the eastern Negev were slightly lower, at 1,140 and 1,100 micrograms per cubic meter respectively, while those in Tel Aviv and Beersheba were 800 and 705 micrograms per cubic meter, the ministry said.
Despite previous predictions that the dusty conditions would fade gradually by Friday, IMS forecasts on Thursday said that the haze would likely persist throughout Friday and even possibly remain into Saturday.
A slight cool-down will likely bring only minimal reprieve from the simultaneously hot conditions on Sunday. Temperatures are still expected to remain unseasonably high through Monday, the forecasts said.