Ellicott City Double Flood Nightmare: Perhaps Climate Change, But Lots Of Other Factors

Aftermath of Sunday's Ellicott City, Maryland on Sunday.

As I noted yesterday, Ellicott City, Maryland, a charming, historic community not far from Baltimore, on Sunday suffered its second devastating, extreme flood in less than two years.

Raging water tore through the city's downtown, gutting buildings, sending cars careering down through the torrents. One person is missing, and once again, Ellicott City is a terrible disaster zone.

If anything, Sunday's flood was worse than the one in July, 2016. Water reported rose somewhat higher than it did in 2016, nearly reaching the second floor of some buildings. Adjacent Cantonsville reported 9.71 inches of rain Sunday, nearly twice the amount that should have fallen in the entire month of May, says Accuweather. 

Accuweather also reports that the Patapsco River near Catonsville rose above 17.8 feet in less than two hours, setting an all-time record at that spot.

CLIMATE CHANGE?

Floodwaters crash through Ellicott City, Maryland on Sunday

We're often told that climate change is bringing about more, and more frequent weather extremes. Is climate change to blame for Ellicott City's double nightmare in 2016 an 2018?

It might be one factor, but there are surely other things going on as well. And most of those other things have nothing to do with global warming.

But I will start with the climate change question. It's impossible, or at least nearly so, to blame one isolated weather event, like Sunday's Ellicott City disaster, on climate change. The only thing we can say is the extreme flood is consistent with climate change.

Here's why we can say that: A warmer atmosphere can hold more water vapor than a cooler one. For every degree of warming, the amount of water vapor the air can hold goes up by roughly 7 percent, says the Center for Climate and Energy Solutions.

That extra water vapor makes the potential for downpours greater, and can make those downpours more intense than they otherwise would be.

Extreme downpours are already becoming more common because of this added atmospheric moisture. The 2014 National Climate Assessment says that between 1958 and 2012, the number of extreme rainfall events increased by 71 percent in the Northeast, 37 percent in the Midwest and 27 percent in the Southeast.

Devastation from Sunday's flood in Ellicott City, Maryland 

Ellicott City on Sunday was certainly an extreme rainfall event. Which means it's possible that the downpour there was worse than it otherwise would have been without climate change.

Both the rainfall rates in 2016 and 2018 are considered once in 1,000 year events, so that's something to note.

A note on that: There's some dispute as to whether either flood was a 1,000 - year event. Slight changes mean big differences in the ratings. According to the Baltimore Sun, some meteorologists consider the 2016 flood a one in 75 year event in terms of rainfall, and Sunday's storm a one in 200 year event.  

That said, there have always been extreme rainfalls, with or without climate change, so the Ellicott city downpour was at least partly dumb bad luck.

OTHER FACTORS

As I noted, there are other very big factors that contributed to Ellicott City's flood, both on Sunday and going back through history. These factors have nothing to do with climate change.

Downtown Ellicott City is in a lousy place. It's along a river, and if flanked by steep hillsides. During heavy downpours, water sweeps down these hills, and has nowhere to go but into the river that goes through downtown Ellicott City. If the river goes over its banks, the city floods. Part of the Main Street in Ellicott City is a fairly steep hill, so the water rushes through.

Ellicott City has been through devastating floods frequently - in 1768, 1817, 1847, 1868, 1901, 1917, 1923, 1952, 1952, 1972, 1975, 1989, 2011, 2016 and now 2018. They shouldn't have built Ellicott City where it is. (However, the 2016 and 2018 floods were the worst, or nearly the worst of the bunch.)

The population in and around Ellicott City has gone up tremendously in recent decades. Undeveloped land consists of fields and forests,  and heavy rains can partly soak into those areas, minimizing the amount of runoff headed toward Ellicott City.

Now, there are so many more parking lots, streets, roofs and other impermeable surfaces than there once was. Which means every time it rains, there's more runoff than there used to be. Which means nine inches of rain in one afternoon would create a worse flood in 2018 than the same storm would have caused 100 years ago.

Ellicott City had barely recovered from the 2016 flood. FEMA had just announced earlier this month that the community had gotten a $1 million flood mitigation grant, which we now learned came too late.

Everybody in Ellicott City must be terribly demoralized today. I do hope the city can recover, and I also encourage local, state and federal governments to find ways to minimize the inevitable future floods there.

Why Is Everybody Ignoring Louisiana?

Louisiana is experiencing the nation's worst
disaster since Superstorm Sandy. Why haven't we
paid more attention to this calamity? 

The question in the headline of this post is being asked more and more in weather geek circles.

The ongoing flood disaster in Louisiana has certainly been in the news, but it hasn't gotten the attention of other calamaties of similar size.  

Louisiana is probably on par with Superstorm Sandy in 2012 in terms of how widespread the destruction is.

The Weather Channel has the latest tally: 

So far, 11 people have died. The flooding had destroyed or damaged at least 40,000 homes. About 30,000 people and 1,000 pets have been rescued. So far, at least 40,000 people have sought FEMA disaster assistance.

In Ascension Parish (parishes are akin to counties in other states) at least 15,00 homes and businesses are flooded. In Livingston Parish, home to 138,000 people before the flood, it's estimated taht 75 percent of the homes are total losses.

I'm sure the death toll will rise. NOLA.com reports that they haven't even really begun door to door searches yet, and there are probably victims in some of these flooded houses.

Bottom line: This is huge.

So why has the media sort of yawned over this one?

Marshall Shepherd, writing in Forbes, has several theories.  Among them: The storm didn't have a catchy name like a hurricane, i.e Katrina.

The news cycle is full of other big stuff: Trump, unrest in Milwaukee, the Olympics are all competing for news viewers. Marshall also says the flood evolved over the weekend, when news organizations aren't nearly as staffed or engaged as they are during the workweek.

Marshall brings up a rather scary, sad reason Louisiana might have been downplayed in the national conscience: There have been so many huge floods lately that this one seems like old hat.  We've had a ever-lengthening string of enormous so-called 500 year floods. South Carolina. Texas. (twice!) West Virginia, Maryland.

And here we go again, another flood. When something becomes routine, it's not news anymore. Of course, if big floods become so common that they aren't news, something's wrong.

It's probably a combination of climate change, which makes epic rain storms and floods more likely, and the fact that we're paving over flood plains that is causing this. (If you pave over forests, marshes and fields with shopping centers and neighborhoods, the water will no longer harmlessly fill up a bayou. It will flow into people's houses instead. )

The fact that floods that wreck thousands of homes, affect thousands of people at one time has become routine and a "new normal" should be frightening to a lot of us.

If this "new normal" means all these victims are ignored, then they don't get the help they need. As NOLA.com put it in a headline: "National Media Fiddles While Louisiana Drowns."

People are doing heroic work in Lousiana to help flood victims. But it takes the glare of the national spotlight to force as much aid into the disaster zone as possible. If the general public is more aware of a catastrophe like Louisiana, the more likely they are to dig into their pockets to help.

Or as NOLA.com put it: "As Louisiana well knows, the loosening of the recovery purse strings is directly commensurate to the number of people who are made aware of the scope of the devastation. In this case, where national news coverage has been scarce, locals have every reason to worry that recovery funds will be just as scarce."

Let's just hope lots of attention, and relief money and supplies for Louisiana flow into the state faster than the flood waters did.





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But broaden the focus a little, and some links appear. The frequency and intensity of heavy rainfall events have increased globally, said Kenneth Kunkel, a climate scientist at NOAA’s National Centers for Environmental Information.

“Each decade, it has been higher than the previous decade, for about the last 30 to 40 years,” he said.

Both the land and the oceans have been warming up, which has increased the amount of water vapor in the atmosphere, he said. The oceanic moisture feeds into the storms that form over land. It is likely that the storm in Baton Rouge last week produced more rainfall than it would have 40 years ago, Kunkel said.