Images of America’s fourth largest city under several feet of water are a reminder that not even the richest country on Earth is immune to the effects of extreme weather. Nearly half a million of Houston’s residents have been directly affected, with at least 30,000 of those in need of emergency accommodation. A handful have died in the rising floods. The cost of clearing up the mess will be immense.

Whenever natural disasters strike, wherever they may occur, their impact on real people is grim and lasting. The flooding this weekend in Texas is of a magnitude that America has not witnessed since Hurricane Katrina left a trail of destruction in its wake, most notably in New Orleans. The failure of flood defences on that occasion resulted in over 100 lives being lost. There may be fewer fatalities this time but many people will find the road to recovery a difficult one.

Plainly, it is difficult to predict with precision the exact amount of rainfall that a storm of this kind will deposit. Nevertheless, Hurricane Harvey was widely forecast to be at least the match of any of its predecessors and in that regard the apparent inability of Houston’s authorities to cope with the consequences is a matter that will require close examination.

Questions are already being asked about the advice to residents of the city to take shelter in their own homes, rather than to evacuate to places of safety. Many who did so were unable to escape by the time the full extent of the flooding started to become apparent – at least 2,000 have had to be plucked to safety by emergency services. Boat owners are being asked to assist official rescuers. On Sunday, 3,000 national and state guard troops were mobilised to help with relief and rescue efforts.

Houston’s mayor, Sylvester Turner, said he had no regrets about deciding against an evacuation order – and he rightly pointed out that such an undertaking in a city of 6.6 million people would be nigh on impossible anyway. Still, the outcome has been that the state authorities simply do not have the resources to respond with requisite speed to every emergency call they receive: that has led to anger among those residents in need of help.

President Trump indicated earlier in the weekend that he would visit the affected area on Tuesday, although with rain still falling it remains to be seen where he will reach landfall. He will need to bring with him more than bombastic platitudes: Texans want hard promises of federal aid and will want those promises swiftly realised. The head of the Federal Emergency Management Agency has already made plain that he expects his organisation to be working in Houston and its environs for years to come, which speaks volumes about the scale of the disaster.

Of course, the President is the world’s most influential climate-change sceptic and it will be interesting to see if his view is blown off course by what he sees in Texas. Hurricanes are nothing new but the US has seen two of its worst storms ever in a little over a decade. And it is such extreme weather events which are – to those who believe – the hallmark of climatic change. Trump is fond of building walls, but weather of this sort tends to find a way through.