Qatar has been hit by more than a year's worth of rain in a matter of hours, almost bringing the country to a standstill and prompting the premier to order an inquiry.
Bad weather across the region also affected neighbouring Saudi Arabia where one person was killed during flooding.
The deluge in Doha blocked several roads, making some impassable for commuters and causing huge congestion.
Schools and malls closed, hotels were affected and the rain forced the US embassy in Qatar to shut down.
Worst hit seemed to be the area around Doha's Hamad International Airport, where almost 80 millimetres of rain fell, according to the Qatar Meteorology Department.
Social media users reported leaks at the facility, which opened just last year after being constructed at an estimated cost of US$17 billion.
However, Hamad International said flights operated normally throughout the day.
The World Bank calculates that Qatar receives, on average, 74 millimetres of rain each year.
In response to the scale of the problems, Qatar's prime minister ordered an investigation, said the official Qatar News Agency.
Sheikh Abdullah bin Nasser bin Khalifa al-Thani said those responsible for "flawed projects" could face possible prosecution.
As many as five unnamed companies could face prosecution, said QNA, citing the government communications' office.
The scale of the disruption was especially worrying as Qatar has undertaken a more than US$200 billion infrastructure program to ensure it is ready for the football World Cup finals, which it will host in 2022.
Matches will be taking place at this exact point in seven years' time.
The rains also affected neighbouring Saudi Arabia where one person was killed during.
Schools were closed for a second day as rain continued to fall on Riyadh, flooding some streets and forcing drivers to abandon their cars.
About 10 cars were submerged under about two metres of water in a highway underpass in the Labban district on the capital's western outskirts, an AFP photographer reported.
Workers were trying to drain the floodwaters into tanker trucks as a light rain fell from gloomy skies.
The Civil Defence agency reported that 72 vehicles had been rescued in the Riyadh region with their occupants unharmed.
One person died in Rimah, northeast of the city, the agency said.