Nearly two dozen people have died in flooding in Saudi Arabia and Oman this week, as heavy rains soaked roads and cities.
Saudi authorities warned of the extreme weather on April 24 but the heaviest precipitation started on Monday, while the flooding in Oman began at around the same time.
Saudi Arabia's civil defence said at least 13 had died there and four were missing across the cities of Riyadh, Baha, Hail, and Quwaiyiah. Hundreds more had been displaced, trapped or injured. Civil defence personnel rescued 937 civilians and moved 695 families to emergency shelters, the agency said in a statement late on Wednesday. More than 4,200 road accidents were reported between Monday evening and mid-day on Wednesday.
Also late on Wednesday, Saudi King Abdullah issued a directive through the Interior Minister, Mohammed bin Nayef, for the Civil defence forces to use "all their potential" to help those affected, including by offering "financial and in-kind aid".
In Oman, local media reported that six citizens had died, including two pairs of brothers. A 17-year-old and his older brother, 19, died while trapped in a wadi in the Dhahirah region, while two brothers aged 3 drowned in a pool at a farm in the coastal region of Batinah. The Royal Omani Police said they had received roughly 200 calls for help and had evacuated at least 70 people from affected areas.
Residents and authorities said the flooding had been some of the most severe in recent years.
"It's unusual weather, but it's something that can happen," said Dr Andy Yaw Kwarteng, head of the Remote Sensing and GIS Centre at Oman's Sultan Qaboos University. "There is still a little more coming for Yemen, the UAE and Qatar," he said of the rains.
As waters have risen, harrowing stories have flooded social media. In Oman, a school bus filled with 30 students was reportedly trapped on a flooded road. After pulling the children to safety, the vehicle was removed from the waters with a crane
Local media in Saudi Arabia captured images of cars being washed away by flood waters and passengers clinging to trees. In one city, Al Kharj, 400 Civil defence personnel were deployed with air support to search for missing persons. The authorities did not say approximately how many were unaccounted for.
Security forces in both countries urged residents to avoid valleys and other dangerous areas at risk of runoff from rains. In a statement on Wednesday, Juma'an Daes Ghamadi, a media spokesman for Saudi Arabia's Civil defence told residents in floodplains to "get out of their homes".
For many Saudi residents, the floods were unwelcome reminders of 2009, when some of the worst flooding in the kingdom's history left more than 120 dead and displaced about 22,000. After the disaster, several officials who approved environmentally flawed construction projects were taken to court, but huge infrastructure challenges remain across the kingdom.
"The main issue is land use," said Dr Mohamed AbdelAziz AbdelHamid, a former professor of urban planning at King Saud University, arguing that building is often undertaken without considering environmental risks.
Building codes are also inconsistent, both on the books and in practice, he said. Federal, district, and city authorities all have their own specifications and they often conflict.
"The problem also comes from the education system," he argued. They don't teach environmental planning in university curriculum."
But Dr Kwarteng in Oman argued that preparation is often impossible for extreme weather patterns such as the Gulf is witnessing.
"Sometimes you have to take what you get," he said from Muscat. "It won't always be easy to find a solution."