Now that the water has receded and the highways have reopened; now that cleanup is well underway and 24 funerals have been planned across Missouri and Illinois; now that a federal disaster has been declared and the loans can be processed, what have we learned from the Great Holiday Week Flood of 2015?

Probably nothing. At least nothing that we didn’t know before and chose to do almost nothing about.

In a city at the confluence of the nation’s two greatest rivers, floods are a fact of life. Like drought in Southern California, tornadoes in Kansas, snow in Buffalo. Public policy can mitigate the effects of severe weather, but flood control has political implications.

Individuals, if they can afford it, move out of the reach of rivers. Communities, too, can leave the flood plains empty so the rivers can stretch. But that means homes and businesses don’t get built. Taxes don’t get paid, people aren’t put to work, powerful people don’t get their way.

If past is prologue, that’s not going to happen. Over the past few days, TV showed a lot of pictures of Gov. Jay Nixon and Sen. Roy Blunt at flood sites, Expressing Concern. Four years ago, after 2011’s Great Flood along the Missouri and Mississippi, both men opposed the Corps of Engineers’ decision to blow a hole in the Birds Point Levee in southeast Missouri to save the city of Cairo, Ill., from disaster. Their concern was for a handful of Missouri farmers, not the people of Cairo.

There’s very little to be gained politically from flood mitigation, and a great deal to be lost. There’s no money in flood control, which depends entirely on action by the United States Congress, where money speaks loudest.

The only time there’s consensus for it is when the waters are rising. By the time meetings get held and decisions get made, the waters have receded. The Great Flood of 2011 was followed by the Great Drought of 2012. Since then more flood plain development has been approved.

Besides, like generals who always prepare for the last war, we’re always worrying about the last flood and every flood is different. In some places, the Holiday Week flood exceeded high-water marks set by the Great Flood of 1993. But that was a slow-motion catastrophe that unfolded over weeks as rain in the upper basins of the river made its way downstream.

The 2011 flood was a disaster on the Missouri in the western part of the state, but by the time the crest got to St. Louis, the levees raised after 1993 were entirely adequate. They weren’t overtopped. They weren’t undermined by boils.

Will they be adequate next time? It depends what the next flood looks like. Pictures and video make every flood look like any other, but that’s an illusion.

The Holiday Week flood looked a lot like the winter floods of December 1982 that sent the Meramec River out of its banks and submerged Valley Park. It was the last straw for Valley Park, which used to flood in heavy dews. After 1982, the levee there was raised to 44 feet. Water trickled over the top at 44.1 last Thursday, but except for the western part of town, the levees were enough. This time.

Of course that meant more water everywhere downstream, from Interstate 44 and Missouri Highway 141 to Arnold. The first two laws of ecology propounded by the late Barry Commoner of Washington University were that everything is connected to everything else, and everything has to go somewhere.

The Holiday Week Flood was a freak, a localized wintertime deluge that — absent abnormal weather conditions in other parts of the Northern Hemisphere — could not have happened. No way that much moisture could be contained in normally cold winter air.

It’s no consolation along the Meramec, nor in Texas where the same weird winter storm spawned killer tornadoes, but we weren’t alone with our bizarre year-end weather. Meteorologists are having a field day explaining how the “polar vortex” was disturbed by a “bomb cyclone” of warmer air transferred (“advected”) northward. Last Wednesday, it was warmer at the North Pole (33 degrees) than it was in Chicago.

And then there’s El Niño, the cyclical weather pattern disturbing ocean currents in the Pacific, causing floods in South America that make ours look puny. Meanwhile, Great Britain is being lashed by near-record rain and snowfall, which may have to do with something called the “Cool Blob.” That melting polar ice is creating colder-than-usual subsurface temperatures in the North Atlantic.

As systems react to these changes, it suggests to some climate forecasters that we’ll see colder-than-normal temperatures in parts of the United States later this winter. Others aren’t so sure: Climate is weather observed over long periods of time, and at any one time and one place, odd things happen.

But wild swings and more frequent extremes are happening as the climate changes. Smart policymakers would read this to mean not only more frequent floods, but more severe weather and deeper droughts. They would not, for example, approve building new homes and shopping centers in 500-year flood plains because nobody knows what that means anymore.

This would be a smart way to go. Which would be something different.

Kevin Horrigan • 314-340-8135

@oldsport on Twitter

khorrigan@post-dispatch.com