Heavy rains lashed the United Arab Emirates on Tuesday, flooding out portions of major highways and leaving vehicles abandoned on roadways across Dubai. Meanwhile, the death toll in separate heavy flooding in neighboring Oman rose to 18 with others still missing as the sultanate prepared for the storm.

The rains began overnight, leaving massive ponds on streets as whipping winds disrupted flights at Dubai International Airport, the world's busiest for international travel and the home of the long-haul carrier Emirates.

Police and emergency personnel drove slowly through the flooded streets, their emergency lights flashing across the darkened morning. Lightning flashed across the sky, occasionally touching the tip of the Burj Khalifa, the world's tallest building.

Schools across the UAE, a federation of seven sheikhdoms, largely shut ahead of the storm and government employees were largely working remotely if able. Many workers stayed home as well, though some ventured out, with the unfortunate stalling out their vehicles in deeper-than-expected water covering some roads.

Authorities sent tanker trucks out into the streets and highways to pump away the water.

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.

Initial estimates suggested over 30 millimeters (1 inch) of rain fell over the morning in Dubai, with as much as 128 mm (5 inches) of rain expected throughout the day.

Rain also fell in Bahrain, Qatar and Saudi Arabia.

In neighboring Oman, a sultanate that rests on the eastern edge of the Arabian Peninsula, at least 18 people had been killed in heavy rains in recent days, according to a statement Tuesday from the country's National Committee for Emergency Management. That includes some 10 schoolchildren swept away in a vehicle with an adult, which saw condolences come into the country from rulers across the region.