For eons, large plumes of dust and sand sweeping across most of Saudi Arabia have been a natural, seasonal aspect of life.

Though a common meteorological phenomenon in arid and semi-arid regions, in recent years scientists have been sounding the alarm over the adverse health and environmental effects of increasing dust storms, prompting Saudi authorities to face the challenges head-on.

The Middle East, Africa and the Arab Gulf are no strangers to sandstorms.

They occur relatively close to the ground surface, but finer dust particles may be lifted miles into the atmosphere, where strong winds transport them long distances and across continents.

Saudi Arabia is a prime location for these extreme sandstorms, as it occupies almost the entire Arabian Peninsula, and is primarily desert with patches of rocky terrain in the west and central regions.

The Kingdom also sits on a majority of the largest desert area in Asia, the Arabian Desert.

The vast expanse of sandy beige and red terrain stretching across the country leaves Saudi Arabia exposed to some of the harshest sandstorms arriving mainly from the north or west.

These storms obscure vision, halt maritime and flight operations, close schools, and harm human health, while turning the cerulean blue skies an ominous orange.

Last month, a transboundary sandstorm engulfed Saudi Arabia, Iraq, Iran, Kuwait and the UAE, sending thousands to hospital as the air filled with fine dust particles that are linked to asthma attacks and the spread of bacteria, viruses, toxins and more.

Depending on the weather and climate conditions, dust can remain in the atmosphere for several days and travel great distances.

Some scientists say that climate change could increase sandstorm frequency and intensity.

According to several studies, the Middle East witnesses one of three types of sandstorms approximately 30 percent of the year.

A reduction of visibility defines the sandstorms; blowing dust reduces visibility to a few feet for brief intervals, and horizontal visibility is less than 11 km.

For dust storms, horizontal visibility is less than 1,000 meters, and for severe dust storms is less than 200 meters.

A 2019 study analyzed the Kingdom’s dust-storm occurrences by studying figure analysis from 27 observation stations provided by the Presidency of Meteorology and Environment, using data on spatial and temporal distribution of atmospheric dust between 2000-2016.

The study noted a significant increase in occurrences, especially in the Eastern Province, with a clear seasonality in the incidence of dust and sand storms.

Great white shark researchers on Cape Cod are reminding visitors that warmer weather signals not just the start of the busy tourist season, but also the arrival of the region’s famous predators.

July tends to be when great whites appear in earnest as the cape’s waters warm, with sightings peaking from August through October, Megan Winton, a scientist with the Atlantic White Shark Conservancy, said during a news conference at the organization’s offices in Chatham on Wednesday.

“Just know that large sharks are here,” she said. “They’re a constant presence from June to the fall.”

A great white sighting forced the temporary closure of Head of the Meadow Beach in Truro on Tuesday.

Greg Skomal, a state marine biologist who has been studying the region’s great whites for decades, said the animals still tend to be concentrated on the Atlantic Ocean-facing side of the cape, where they feast on a flourishing seal population.

He advised beachgoers to be most vigilant when swimming off beaches where the shoreline quickly drops off into deeper waters.

“Sharks will come close to the shore when they have water depth,” Skomal said.

Since 2009, researchers have tagged more than 280 great whites off the cape, with nearly 230 of those tags still active and sending back data about shark movements, according to the scientists.

Skomal says there’s been a marked change in beachgoer behavior since the region saw two shark attacks on humans — one of them fatal — in 2018.

Many are increasingly keeping closer to shore when they swim, with others not venturing into the waters at all, he said.

“It’s a conservation success story in terms of sharks and seals,” Winton said. “At the same time, this is an important place for people to recreate, so it’s important to find ways to coexist.”