Scenes of flood-ravaged neighborhoods in one of many planet’s driest areas surprised the world this month. Heavy rains within the United Arab Emirates and Oman submerged vehicles, clogged highways and killed at the very least 21 folks. Flights out of Dubai’s airport, a serious world hub, have been severely disrupted.

The downpours weren’t a complete shock — forecasters had anticipated the storms a number of days earlier and issued warnings. However they have been actually uncommon.

Right here’s what to know.

Heavy rain there’s uncommon, however not unheard-of.

On common, the Arabian Peninsula receives a scant few inches of rain a yr, though scientists have discovered {that a} sizable chunk of that precipitation falls in rare however extreme bursts, not as periodic showers. These rains usually come throughout El Niño circumstances like those the world is experiencing now.

U.A.E. officers mentioned the 24-hour rain complete on April 16 was the nation’s largest since data there started in 1949. And components of the nation had already skilled an earlier spherical of thunderstorms in March.

Oman, with its shoreline on the Arabian Sea, can also be susceptible to tropical cyclones. Previous storms there have introduced torrential rain, highly effective winds and mudslides, inflicting in depth injury.

World warming is projected to accentuate downpours.

Stronger storms are a key consequence of human-caused world warming. Because the ambiance will get hotter, it will probably maintain extra moisture, which may ultimately make its manner right down to the earth as rain or snow.

However that doesn’t imply rainfall patterns are altering in exactly the identical manner throughout each a part of the globe.

Of their newest evaluation of local weather analysis, scientists convened by the United Nations discovered there wasn’t sufficient information to have agency conclusions about rainfall tendencies within the Arabian Peninsula and the way local weather change was affecting them. The researchers mentioned, nonetheless, that if world warming have been to be allowed to proceed worsening within the coming many years, excessive downpours within the area would fairly possible change into extra intense and extra frequent.

Sizzling oceans are a giant issue.

A global workforce of scientists has made a primary try at estimating the extent to which local weather change could have contributed to April’s storms. The researchers didn’t handle to pin down the connection exactly, although of their evaluation, they did spotlight one recognized driver of heavy rain within the area: above-normal ocean temperatures.

Massive components of the Indian, Pacific and Atlantic Oceans have been hotter than regular just lately, partly due to El Niño and different pure climate cycles, and partly due to human-induced warming.

When wanting solely at El Niño years, the scientists estimated that storm occasions as rare as this month’s delivered 10 p.c to 40 p.c extra rain to the area than they’d in a world that hadn’t been warmed by human actions. They cautioned, nonetheless, that these estimates have been extremely unsure.

“Rainfall, typically, is getting extra excessive,” mentioned Mansour Almazroui, a local weather scientist at King Abdulaziz College in Jeddah, Saudi Arabia, and one of many researchers who contributed to the evaluation.

The evaluation was carried out by scientists affiliated with World Climate Attribution, a analysis collaboration that research excessive climate occasions shortly after they happen. Their findings about this month’s rains haven’t but been peer reviewed, however are based mostly on standardized strategies.

The position of cloud seeding isn’t clear.

The U.A.E. has for many years labored to extend rainfall and enhance water provides by seeding clouds. Basically, this entails capturing particles into clouds to encourage the moisture to collect into bigger, heavier droplets, ones which are extra prone to fall as rain or snow.

Cloud seeding and different rain-enhancement strategies have been tried internationally, together with in Australia, China, India, Israel, South Africa and the USA. Research have discovered that these operations can, at greatest, have an effect on precipitation modestly — sufficient to show a downpour into an even bigger downpour, however most likely not a drizzle right into a deluge.

Nonetheless, specialists mentioned pinning down how a lot seeding might need contributed to this month’s storms would require detailed research.

“Typically, it’s fairly a problem to evaluate the impression of seeding,” mentioned Luca Delle Monache, a local weather scientist on the Scripps Establishment of Oceanography in La Jolla, Calif. Dr. Delle Monache has been main efforts to make use of synthetic intelligence to enhance the U.A.E.’s rain-enhancement program.

An official with the U.A.E.’s Nationwide Middle of Meteorology, Omar Al Yazeedi, instructed information shops that the company didn’t conduct any seeding through the newest storms. His statements didn’t clarify, nonetheless, whether or not that was additionally true within the hours or days earlier than.

Mr. Al Yazeedi didn’t reply to emailed questions from The New York Instances, and Adel Kamal, a spokesman for the middle, didn’t have additional remark.

Cities in dry locations simply aren’t designed for floods.

Wherever it occurs, flooding isn’t only a matter of how a lot rain comes down. It’s additionally about what occurs to all that water as soon as it’s on the bottom — most critically, within the locations folks dwell.

Cities in arid areas usually aren’t designed to empty very successfully. In these areas, paved surfaces block rain from seeping into the earth beneath, forcing it into drainage programs that may simply change into overwhelmed.

One current research of Sharjah, the capital of the third-largest emirate within the U.A.E., discovered that town’s speedy development over the previous half century had made it susceptible to flooding at far decrease ranges of rain than earlier than.

Omnia Al Desoukie contributed reporting.