‘It’s Just Insanity.’ Louisiana flood a sign of things to come?

The historical magnitude of last week's devastating Louisiana flood event is still coming into focus. Many locations are still dealing with floodwaters from unprecedented 2-day rainfall totals between 20 and 30 inches.

Parts of Louisiana have received more rainfall in 4 days than most of Minnesota gets in an average year. More than Los Angeles has seen in several years.

Climate change links

The evolving science of climate change attribution for extreme weather events is getting better at pinpointing links between earth's warming climate and individual extreme weather events. In my early assessment, it's highly likely climate change fingerprints are all over the Louisiana flood event of 2016.

Barry Keim is the Louisiana state climatologist. I know my share of climatologists. They're usually pretty reserved in describing big weather events. So when I hear scientists like Barry use words like "insanity" to describe what just happened in Louisiana, it gets my attention.

Climate Central's Andrea Thompson has this angle on the evolving analysis of Louisiana's extreme 1,000-plus rainfall event.

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The staggering rains that swamped some 60,000 houses in southern Louisiana and shattered the previous state rain record are the latest — and perhaps most remarkable — in a string of jaw-dropping rain events across the U.S. over the past year.

From South Carolina to Houston to West Virginia and Ellicott City, Md., each instance of extreme rainfall and subsequent flooding raises questions about the potential role of climate change in making such events more likely.

Storms are expected to unleash more rain in the future as the world continues to heat up and an uptick in heavy rainfall events in the U.S. over the past few decades is already evident.

So-called attribution studies have pointed to increased odds of certain events thanks to rising global temperatures, but what about the recent spate of intense rain events? What can we say about the potential role of global warming in juicing such a seemingly remarkable streak?

‘It’s Just Insanity’

Even amongst the array of other mind-boggling rain and flood events around the U.S., the recent Louisiana disaster stands out.

The slow-moving storm continuously pulled moisture from the Gulf of Mexico, dumping rain over the same area for hours and hours. The Baton Rouge airport recorded 32 straight hours of rainfall, from the night of Aug. 11 through the morning of Aug. 13.

“It literally rained, for me, every waking minute of the day on Friday,” Barry Keim, the Louisiana state climatologist, said. “There was never a moment when it was not raining at my house.”

For Baton Rouge, a 1-in-100-year rain event (or one that has a 1 percent chance of happening in any given year), would be 14 inches falling over two days. That would already be a “pretty rare event,” Keim, who also studies climate extremes at Louisiana State University, said.

A 1-in-1,000-year event — “we’re talking about something that’s not likely to ever happen” — would be 21 inches falling over the same time period, he said.

There were nine stations in the area that topped that 1-in-1,000 level, two of which saw more than 25 inches in just two days. The highest rainfall was recorded in Watson, La., which saw 31.39 inches. That obliterated the previous two-day rainfall record by more than 7 inches.

“It’s just insanity,” Keim said.

Half of southern Louisiana received 10 inches or more of rain, and it’s possible that more homes were flooded in this event than by Hurricane Katrina, Keim said. Many of those homes hadn’t flooded during the previous flood of record, in 1983, or at any time since.

“The whole region just got absolutely hammered,” Keim said.

Mashable's Andrew Freedman pens this big picture look at how the extreme weather events of 2016 are falling into place with climate change.

In the U.S. and around the world, this has been a summer of extreme weather that has astonished veteran meteorologists, and brought hardship to millions. Record heat waves, deadly floods, massive wildfires and even a climate-related anthrax outbreak have left their mark from Siberia to California.

Louisiana Flooding

In Louisiana right now, tens of thousands of residents are beginning the long process of putting their lives back together after a 1,000-year-deluge caused historic flooding that led to more than 30,000 rescues and at least 13 deaths.

For many areas, this was an unprecedented event.

More rain fell in Watson, Louisiana in just a few days - 31.39 inches - than typically falls in an entire year in Minneapolis or San Francisco, for example.

Near-record warm water temperatures in the Gulf of Mexico contributed to the deluge, which began late last week and continued through the weekend. Global climate change also played a part in this disaster by increasing the amount of moisture the atmosphere can hold, which goes up by about 7 percent for every degree Celsius in warming.

When the damage is finally tallied from the Louisiana floods, the bill is likely to run into the billions of dollars. The Red Cross, for example, says this was the worst natural disaster to strike the U.S. since Hurricane Sandy in 2012. Only a minority of homeowners hit with flooding likely had flood insurance, according to news reports.

Communication challenges

How do we get your attention with devastating storms that have no name? Capital Weather Gang's jason Samenow has some good perspective.

It can happen in Minnesota

Yes this was a Louisiana, Gulf Coast-sized flood. But extreme rainfall events are increasing in frequency in Minnesota too. Our weather future in Minnesota very likely includes more unprecedented flood event in the coming years. I am almost certain many neighborhoods that have never seen significant flooding will be underwater in the next few years as the trend lines for extreme rainfall events increase.

There are many ways to prepare for future flood events in Minnesota. Buy and install a bigger sump pump. Dial back your lawn watering at your home, or talk to your association about reducing water use from lawn irrigation systems. If the soil around your foundation is saturated before the next multi-inch rainfall your risk of basement flooding, and financial losses, goes up dramatically. Take a look at how water drains on your property. If you can improve drainage that may help.

The latest climate science says the future of Minnesota includes more mega-rainfall events ahead.