Memorial Day Floods: a natural phenomenon

Flooding changed the face of Houston Monday and Tuesday, turning the peaceful bayou into a raging torrent swelling beyond its banks, spilling over major highways and washing into communities where it did its worst damage. Busy roads turned into lakes of steaming vehicles as hundreds were lost in the floodwaters, and some 1,400 structures were critically damaged.  In the wake of the storms across the Southwest that killed at least 17 people, Gov. Greg Abbot declared 24 Texas counties disaster areas, tacking them on to the 13 counties already under declarations due to weather. To make matters worse, scientists are beginning to attribute the current rainy weather to El Niño, predicting a wet summer that could see more continuous rainfall.


Floodwaters rise in Houston Memorial Day. The water claimed an estimated 1,200 homes. Flickr Creative Commons.

When it comes to disasters, floods are serious business. In the U.S. each year, floods account for about $6 billion in damages, and floodwaters claim about 140 lives. Around the world, coastal flooding causes about $3 trillion in damages. It may seem like you can just power through rising water in your vehicle, with the confidence that if you’re in trouble, you can just swim to safety, but the safest route to take is to turn around, don’t drown. Get to higher ground.


Stranded motorists abandoned their cars to the floodwaters Memorial Day. Flickr Creative Commons.

Flash flooding occurs with heavy or continuous rainfall over an extended period of time, sometimes in areas nowhere near the location of the heaviest precipitation. Water runs downhill, filling riverbeds and waterways to capacity, and when the water doesn’t stop, it spills over the banks and into the flat areas beyond, called the flood plain. Meteorologists measure flood risk in years. The risk of flooding in the 100-year flood plain is about one percent every year; that makes flood risk in a 50-year flood plain two percent, and in a 500-year flood plain, one-half percent.

Global climate change might account for more common and stronger floods in Texas and worldwide, according to National Geographic, and information from the NOAA supports this claim. Floods in Texas do appear to have worsened in recent years. In 1998, a “perfect storm” involving two hurricanes and a stationary cold front led to a disastrous flood in Central Texas, swelling the banks of the Guadalupe River into the San Antonio metro area. More than 30 inches of rain fell in a small area south of San Marcos in 36 hours in what was classified as a rare, 500-year flood event.


Floodwaters rise near Allen Parkway Memorial Day. Flickr Creative Commons.

Four years later, yet another 500-year flood occurred in the same area, doing even greater damage over a larger part of the state. A low pressure system that formed over the northern Gulf of Mexico moved inland and stayed put, dumping record-breaking rainfall over San Antonio and several other counties in the hill country. Two massive, rare Texas floods in four years seems to spell doom for our state and the state of the planet as a whole. However, natural cycles suggest otherwise.

The extreme wet season in Texas and Oklahoma signals an El Niño year, scientists say. Few people may care about the weather phenomenon or understand it completely; they only know the cycle of drought and flooding in the south, of heavy snows and mild winters in the north. Scientists themselves don’t fully understand the causes and effects of El Niño, but they do know that oceanic and atmospheric phenomena are directly linked in the system, NOAA Meteorologist Tom DiLibertero told Al Jazeera.

El Niño occurs in cycles between two and seven years, officially named the ENSO, or El Niño Southern Oscillation in the scientific community. Cold water upwellings normally keep surface temperatures of the Pacific Ocean cool, but when that system fluctuates, the massive body of water warms in the sun. In turn, winds carry more moisture into the air which oceanic winds push over the Americas. Poised in the middle of the continent, this weather dumps heavy precipitation. In years following particularly strong El Niño patterns, the opposite occurs. When cool water returns to the surface of the Pacific, moisture stays closer to Indonesia, creating dry La Niña conditions for the continental U.S. Scientists agree this may be a natural pattern, but the degree to which climate change and warmer global ocean temperatures might worsen its effects is still uncertain.


The new Hamman Hall of Texas Coastal Ecology offers solutions to how we can be better stewards of our coastline.

Add to this that Houston was built on a wetland, an area known for flooding as a natural process, and you’ve got a recipe for disaster every few years. Floods can occur in other places from spring snowmelt, log jams, and broken levees, but for our area, the biggest threat is steady rainfall. After heavy rains from frontal systems and hurricanes alike, the rivers that feed the bayous swell and overflow into lowland areas we’ve built our city over.


In the Hamman Hall of Texas Coastal Ecology, guests can learn about the unique ecosystems of the Upper, Middle and Lower Texas Coast and how flooding affects them as a natural process.

In truth, flooding anywhere is natural and has been happening for millions of years, and humans have capitalized on the benefits of these raging waters around the world. It’s what we do as a species. “Famously fertile floodplains like the Mississippi Valley in the American Midwest, the Nile River valley in Egypt, and the Tigris-Euphrates in the Middle East have supported agriculture for millennia because annual flooding has left millions of tons of nutrient-rich silt deposits behind,” states National Geographic.


Placard information in the Hamman Hall of Texas Coastal Ecology spells out the damages Hurricane Ike caused to Houston and statewide in 2008.

The Weather Channel compared the Memorial Day flooding to other historical floods, including those caused by Hurricane Ike (2008) and Tropical Storm Allison (2001). “According to NOAA’s National Climatic Data Center, there were 86 days with reports of flooding or flash flooding in Harris County from 1996 through 2014,” their report states. “This equates to an average of 4-5 days of flooding each year over that time period.”


At the Do the Weather with Chita Johnson exhibit, a student learns how flood warnings are broadcast over television.

During the Memorial Day event, the water in some Harris County bayous exceeded totals measured during both storms, The Weather Channel found. Buffalo Bayou at Shepherd Drive crested at 33.73 feet Memorial Day, 32.4 feet during Hurricane Ike, and 40.2 feet during Tropical Storm Allison. Brays Bayou at Beltway 8 reached 65.9 feet this year and crested at 58.7 feet during Ike. And Greens Bayou at Shepherd Drive peaked at 34.02 feet Memorial Day, 36.2 feet during Ike, and at 44.04 during Allison. But these hurricanes are only two of the numerous flood events that have soaked Houston in the past 40 years alone.


At the Do the Weather with Chita Johnson exhibit, a student reads a mock-up of what a meteorologist might say during a flood event.

From The Weather Channel: April 2009; 2,100 homes flooded, freeways impassible. June 2006; 11 inches of rain, 3,000 homes flooded. Late summer 1998; Tropical Storm Frances and two other events flood a total of 2,700 homes. October 1994; 22,000 homes flooded, $900 million in damages, 17 killed. (Now that’s one awful flood.) June and July 1989; two separate events flood a total of 2,500 homes. September 1983; a nine-inch deluge floods 1,000 homes along Brays Bayou. July 1979; Tropical Storm Claudette dumps a record 43 inches in 24 hours, flooding 15,000 homes and damaging 17,000 vehicles.

The devastation that flooding has caused for the residents of Houston over the years is heartbreaking, but as disturbing as these number are, it’s no surprise that Houston gets its rain, and that floods happen. They nourish the ecosystem of the Upper Texas Coast and the Galveston Bay area, and it could be hundreds of years before they stop, if not thousands. For Houston, since its founding, flooding has come with the territory.


In the Hamman Hall of Texas Coastal Ecology, young students learn about coastal management using touch-screen technology.

Our species moved here to carve out a life and began retro-fitting the land to suit our needs, just like we’ve always done. In 1836, Houston was established on the banks of Buffalo Bayou, where trees, good soil, and slow-moving water helped rapidly establish a community. As the city continued to grow, it became a vital hub for energy and transportation, and a vital port to Texas and the southern U.S.

Agriculture establishes civilization; infrastructure moves it forward. Doesn’t mean it’s bad. Beavers do it when they change the course of a river with their dams; ants do, too, when they manipulate the soil or a tree to build networks of tunnels; birds do it to create nests and rookeries; coral and oysters build their own habitat and create hundreds of thousands of square miles of reefs around the world.

That’s why conservation and awareness of the natural cycles of our environment, wherever we choose to live, is imperative to our survival. As we encroach upon wetlands for our cities, we must understand that floods will continue to happen. Wetlands act as “natural flood buffers,” states National Geographic. If we live in the buffer, we’re bound to get soaked.


Learn more about the coastal environment at the newly-opened Hamman Hall of Coastal Ecology, and see how weather forecasters spread the word about flood events on live TV when you Do the Weather with Chita Johnson, both at the Houston Museum of Natural Science. If you or your family was affected by the flood, visit the Texas Organization Project for resources that can help you recover.


Science & The Simpsons, Part I: What’s a fossil fuel anyway?

When The Simpsons started in the late 1980s, very few people would’ve believed that the show could last as long as it has. Like the show or not, you can’t deny how it’s changed the way TV shows look at controversial material and incorporate current events and topics into their plots.

For instance, take Episode 450, “Married to the Blob,” which aired this past January. While the main story line deals with Comic Book Guy’s search for love, in quasi Much Ado About Nothing fashion, the first few minutes of the episode regale us with yet another adventure from the show’s favorite superhero, Radioactive Man.

And therein lies the show’s genius — what seems to be a short aside (an introduction at best) is actually an acute commentary on energy literacy: reflecting some of the struggles the industry faces as we seek to maintain energy independence, all while steadfastly moving into the future of energy production.

The show personifies all major aspects for retrieving and releasing energy. Nuclear energy (fission) is represented by Radioactive Man, and his sidekicks Solar Citizen and Wind Lad represent solar and wind power respectively. In this episode, they face their nemeses, a rough group of villains who call themselves The Fossil Fuel Four. They’re made up of King Coal, Petroleumsaurus Rex, Charcoal Briquette, and the Fracker (the names are likewise pretty opaque, with the characters representing coal, petroleum, charcoal, and the technique of fracking). Through their battle, we see the struggle between sustainable resources and fossil fuels.

It would be difficult to overstate the importance fossil fuels have had in creating the modern industrial world. The Industrial Revolution would’ve never occurred without ready access to coal, and the industrialized world still depends on it to a great extent. Fossil fuels have provided a ready source of energy for centuries now because they are easily burned to release their stored energy. When these fuels burn, they oxidize releasing carbon dioxide and water and produce large amounts of energy relative to their weight. These fuels can be found in solid, liquid and gaseous states (like coal, oil, and natural gas).

As these resources have become more scarce, new techniques have been developed to extract them from the earth, such as fracking (technically called hydraulic fracturing, which uses controlled explosions to break up the bedrock where these fuels are held) and surface mining (which removes vast amounts of surface rock to gain access to minerals).

Part of the reason why these new techniques have come into use is that fossil fuels are not easily or readily replenished. They are — quite literally — fossils, and therefore take a long time to form. (The word fossil simply means “evidence of past life.”) Over millions of years, tiny plants and other organisms would settle on the floor of a body of water (ocean, lake, etc.). Other sediment would settle over them, causing them to decompose in anoxic (read: with depleted oxygen) environments. After hundreds of millions of years of exposure to heat and pressure from added sediment, the organic matter is chemically altered. Depending on the type of organic matter, the amount of time and pressure applied, you get different types of fossil fuels.

It’s the depletion of fossil fuels and the negative consequences from them (such as poor air quality, which can lead to smog and acid rain, and the massive amounts of carbon dioxide released into the atmosphere, which has caused drastic changes in climate) that has led to our current quest for sustainable energy sources.

Editor’s note (Please read the following bold text in a cheesy, comic-announcer-type voice): Will climate change continue unabated? What will happen to Radioactive Man now as he battles The Fossil Fuel Four? Will he defeat his foes — or is it too late? 

Tune in next time as we catch up with our superhero.

Solar Sunspots Hibernation?

Is the cycle of sunspots going dormant for an extended period?

That’s what astronomers suggested at the June 14 annual meeting of the American Astronomical Society’s solar physics division, held at New Mexico State University. Frank Hill, associate director of the National Solar Observatory’s Solar Synoptic Network announced, “The solar cycle may be going into a hiatus.”

First, let’s review what a solar cycle is.

Check out my previous blog on the topic.

Like all fluid bodies in our solar system, the sun has a magnetic field.  Where these field lines intersect the sun’s surface, convection from inside the sun is blocked, resulting in a cooler region on the sun’s surface.  The cooler region is darker because it emits more infrared light, which is invisible to our eyes.  The number of sunspots on the sun is not constant but varies over a period of about eleven years.  Since we began keeping systematic track of sunspots, scientists have observed 23 such cycles.

02 Sun Structure
Creative Commons License photo credit: Image Editor

However, the most recent solar minimum lasted much longer than we expected.

We had hoped to begin seeing sunspots in 2008 or 2009, leading to a 2012 peak.  Instead, solar minimum persisted until 2010.  Scientists now expect the current cycle (#24) to peak in May 2013.

According to Frank Hill, several lines of evidence point to a larger trend, in which solar maxima become delayed as well as less and less pronounced, possibly resulting in an extended period largely without sunspots.  One involves the solar ‘jet stream,’ a stream of plasma inside the sun which is analogous to jet streams in Earth’s atmosphere.  About every 11 years, such streams of plasma form near the poles of the sun and then migrate towards the sun’s equator.  When they reach a latitude of about 22 degrees, more sunspot formation is allowed.

Although cycle 24 is well underway, Hill attempted to detect the solar jet stream that will start cycle 25, which in theory should already be forming in the polar regions.  He was unable to do so, leading him to believe the solar cycle 25 may be delayed and its maximum smaller than for cycle 24.

Also, astronomers Matt Penn and William Livingston, upon analyzing 13 years of sunspot date taken at Kitt Peak in Arizona, determined that magnetic fields associated with sunspots now are weaker than during cycle 23.  If the trend continues, these magnetic fields could become too weak to inhibit convection at the sun’s surface, thus preventing sunspot formation.

This may mean that future solar cycles (25, 26, etc.) will have only very small maxima, resulting in a decades-long period of few if any sunspots.

A sunspot viewed close-up in ultraviolet light, taken by the TRACE spacecraft

The last time this happened was the Maunder Minimum, which occurred roughly from 1645-1715.

Astronomers of the day, such as Giovanni Cassini and Johannes Hevelius, were making systematic observations of the sun, and they noted very few sunspots – only about 50 over one 30-year period.  A less severe drop in sunspot activity, called the Dalton Minimum, occurred in the early ninteenth century.  Each of these extended minima were associated with below average temperatures on Earth.  For example, the Great Frost of 1708-09 was among the worst winters in recorded history.

However, not all solar scientists agree that another Maunder Minimum is on the way.

Douglas Biesecker of the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center points out that cycle 24’s polar jet stream formed about eight months after solar minimum and remained patchy for up to 30 months after that. It may still be too soon after the last solar minimum (December 2008) to draw conclusions about that jet.

Also, Biesecker points out that the raw data on the graph showing the weakening of the magnetic fields in sunspots is scattered and indeterminate enough to allow other analyses.

Of course, only the real sun will determine who’s correct on this issue, and you can observe the real sun right here at the Museum.

Our sundial has three sets of holes aligned with the sun’s midday position at each solstice and at the equinoxes.  As we are  now just past the summer solstice (which occurred at 12:17 p.m. June 21), anyone willing to brave the heat can come to our sundial near local noon (1 p.m. during Daylight Saving Time) and project an image of the sun onto a sheet of paper.  Any sunspots present will be revealed.

Science Doesn’t Sleep (9.8.08)

Bacteria loves milk.
Creative Commons License photo credit: IRRI Images

So here’s what went down after you logged off.

A NASA administrator insists he backs the upcoming retirement of the space shuttle (leaving the U.S. unable to send astronauts to the International Space Station)  – despite a leaked e-mail to the contrary. Oh – and, the BBC reports that Chinese astronauts (called yuhangyuan) will perform their first-ever spacewalk.

Got bacteria? New research indicates that you shouldn’t be washing your antibiotics down with milk.

Bad news for mathletes: using your brain might be making you fat.

NPR asks: Can physicists be funny? (The answer is YES.) Scientists at CERN are going through improv comedy training to help reassure the public that they’re not about to create a giant black hole that will swallow the Earth.

Arctic permafrost holds twice as much carbon as the atmosphere – making it a potential environmental threat. Good thing it’s not melting at a disturbingly fast pace.

Does the President need to be tech-savvy?