Heavy thunderstorms dumped more than a year and a half’s worth of rain on Dubai in the span of hours as it flooded out portions of major highways and its international airport.

In neighbouring Oman, the death toll from separate heavy flooding rose to 18, with others still missing as the country braced for the storm. The downpour in the United Arab Emirates (UAE) began late on Monday, April 15 drenching the sands and roads with approximately 0.79 inches of rain, according to meteorological data collected at Dubai International Airport.

The storms intensified around 9am local time on Tuesday, April 16 and continued throughout the day, bringing further rain and hail to the already overwhelmed city. By the end of Tuesday, over 5.59 inches of rainfall had soaked the desert city-state in a 24-hour period.

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Dubai International Airport, the world's busiest for international travel and a hub for the long-haul carrier Emirates, typically sees an average annual rainfall of 3.73 inches. At the airport, standing water could be seen on taxiways as aircraft landed. The airport was forced to halt arrivals on Tuesday night, and passengers struggled to reach terminals due to the floodwater covering surrounding roads.

Emergency services slowly navigated the flooded streets of Dubai, their emergency lights illuminating the darkened roads. The city's driverless Metro also experienced disruptions and flooded stations.

Schools across the UAE largely shut ahead of the storm, while many workers stayed home. Those who did have to go out risked breaking down, as hundreds of vehicles stalled in deeper-than-expected water covering some roads.

Authorities sent tanker trucks out into the streets and highways to pump away the water. Water poured into some homes, forcing people to leave their houses. The country's hereditary rulers offered no overall damage information or injury information for the nation, as some slept in their flooded vehicles on Tuesday night.

In Ras al-Khaimah, the country's northernmost emirate, police said one 70 year old man had died when his vehicle was swept away by floodwater.

Fujairah, an emirate on the UAE's eastern coast, saw the heaviest rainfall on Tuesday with 5.7 inches if rain.

Authorities cancelled school and the government instituted remote work again today, Wednesday.

Rain is unusual in the UAE, an arid, Arabian Peninsula nation, but occurs periodically during the cooler winter months. Many roads and other areas lack drainage given the lack of regular rainfall, causing flooding.

Rain also fell in Bahrain, Qatar and Saudi Arabia.

In neighbouring Oman, at least 18 people had been killed in heavy rains in recent days, according to a statement from the country's National Committee for Emergency Management. That includes 10 schoolchildren swept away in a vehicle with an adult.

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