What is the La Nina? did it impact this hurricane season?

What is the La Nina? did it impact this hurricane season?

I think we can all agree it has been one crazy hurricane season.  We have gone through the entire alphabet, and much of the Greek alphabet, naming storms – a record 30.  Here in Pensacola we had Sally, but we had to prepare for many others that were wobbling around out there.  It seemed this year the computer models were struggling predicting landfall locations.  The “spaghetti” paths of the recent Eta were all over the Gulf.   So, what is going on?  It probably has to do with a warmer Gulf but there has to be more to it than that.  Some have mentioned that it has been a La Nina year, and that the Gulf is more active during such years.  Fair enough… what is the La Nina?

 

It is the opposite of the El Nino – a term more people have heard of.  Okay… what is the El Nino?

The red indicates warm water temperatures. Notice the warm temps in the eastern Pacific – not normal.
Graphic: NOAA

 

 

The El Nino is a warming trend observed in the eastern Pacific Ocean every 2-7 years around Christmas time.  El Nino… “the child”.  There are records of this event going back over a century.  It was first noticed by Peruvian fishermen, who fish some of the most productive waters on the planet.  These productive waters are fueled by the cold Humboldt Current and an upwelling bringing nutrient rich cold waters from the seafloor.  When the El Nino occurs the Humboldt Current warms and “caps” the upwelling from reaching the surface where the food chain can benefit.  The fish move away, and the fishermen notice it.  When people began to colonize southern California, and began fishing for tuna and sardines, they noticed the same thing.  The El Nino moved north of the equator just as it moves south of it. 

 

To better understand this, we will need to know a little about the ocean currents. 

The world rotates on its axis every 24 hours – there, we are off to a good start. 

The sun’s rays hit the earth more directly in the equatorial part of the planet, making it warmer there. 

The cold polar water is more dense and sinks.  The warmer equatorial waters move across the surface of the ocean to fill the void left by the sinking polar water.  But it does not move in a straight line to that point.  The world is turning remember, and this cause the moving water to bend in a curved pattern.  The equatorial water moves west by northwest, warming more as it moves.  This is the equatorial current.  When it reaches Indonesia it is a balmy 80F+ (or so).  This is the land of palm trees and coral reefs – “Bali-Hai”. 

The equatorial currents of the Pacific.
Image: NOAA

The water now moves north towards Japan and Korea before heading towards Alaska.  Here it is called the Kuroshio Current and here it slowly begins to lose its warmth.  As it slides beneath Alaska heading for Canada it is called the North Pacific Current, and then becomes the California Current as it passes the western United States heading back towards the equator.  Here the water is much cooler (60-70F).  There are no coral reefs, but you do find palm trees in southern California.  This coast is also bathed with an upwelling and supports a rich fishery.  

 

The southern Pacific is the same – but the current names are different.  The equatorial current heads west reaching Indonesia and heads south to Australia where they call it the East Australian Current (the EAC of Finding Nemo fame).  This is the home of the Great Barrier Reef.  The currents circle near Antarctica, become colder, and head north along South America as the Humboldt Current (also known as the Peru Current). 

 

Now imagine this…

Imagine the warm equatorial water near Indonesia begins to slide back towards California and Central America.  Imagine this warm water layer then heads north and south to the coasts of California and Peru.  This warm water caps the upwelling and the fish leave – near Christmas time – the El Nino.  Bad times for the fishing fleet. 

Commercial fishing in the California Current.
Photo: NOAA

The atmosphere responds to these ocean temperature shifts.  Normally, the cooler waters reaching the equator from California and Peru move westward forming the equatorial current.  This cool water helps form east winds that move across westward as well.  Known as the Trade Winds, sailors have used them for centuries to reach “good trading locations”.  They are steady and dependable… unless it is an El Nino year.  During El Nino the warmer ocean slows the strength of these winds.  They actually move eastward across Central America and impact the Gulf of Mexico.  During El Nino years these eastward moving Pacific winds push hurricanes out of the Gulf into the Atlantic.  These are the hurricane seasons when Bermuda is hit frequently. 

 

La Nina is the opposite.  The Pacific waters moving into the equatorial area from California and Peru are colder than normal.  These colder waters move faster and farther across the equatorial waters of the Pacific increasing the Trade Winds moving west… not east.  With these Trade Winds moving in the direction they should, even stronger than normal, hurricanes are “sucked” into the Gulf of Mexico.  La Nina seasons are very busy hurricane seasons for us.  And you guessed it, it is a La Nina year.  La Nina usually follows the El Nino and we can sometimes experience them for two seasons, but 12 months is typical. 

 

The thing is La Nina’s have been occurring for centuries.  We have certainly had hurricane seasons that were busier than normal but not to the extent we saw this year.  You have to look at climate change in general, and other atmospheric conditions that could influence this.  I am sure the meteorologists and climatologists are as interested in what happened (is happening) this year as we are. 

 

Hopefully we will not see another season like this for some time. 

Happy Thanksgiving. 

Septic System Do’s and Dont’s After a Flood


Special care needs to be taken with your septic system after flooding. Image: B. White NASA. Public Domain

During and after floods or heavy rains, the soil in your septic system drainfield can become waterlogged. For your septic system to treat wastewater, water needs to drain freely in the drainfield. Special care needs to be taken with your septic system under flood conditions.

A conventional septic system is made up of a septic tank (a watertight container buried in the gound) and a drainfield. Image: Soil and Water Science Lab UF/IFAS GREC.

A conventional septic system is made up of a septic tank and a drainfield or leach field. Wastewater flows from the septic tank into the drainfield, which is typically made up of a distribution box (to ensure the wastewater is distributed evenly) and a series of trenches or a single bed with perforated PVC pipes. Wastewater seeps from these pipes into the surrounding soil. Most wastewater treatment occurs in the drainfield soil. When working properly, many contaminants, like harmful bacteria, are removed through die-off, filtering and interaction with soil surfaces.

What should you do if flooding occurs?

The U.S. Environmental Protection Agency (EPA) offers these guidelines:

  1. Relieve pressure on the septic system by using it less or not at all until floodwaters recede and the soil has drained. Under flooded conditions, wastewater can’t drain in the drainfield and can back up in your septic system and household drains. Clean up floodwater in the house without dumping it into the sinks or toilet. This adds additional water that an already saturated drainfield won’t be able to process. Remember that in most homes all water sent down the pipes goes into the septic system.
  2. Avoid digging around the septic tank and drainfield while the soil is waterlogged. Don’t drive vehicles or equipment over the drainfield. Saturated soil is very susceptible to compaction. By working on your septic system while the soil is still wet, you can compact the soil in your drainfield, and water won’t be able to drain properly. This reduces the drainfield’s ability to treat wastewater and leads to system failure.
  3. Don’t open or pump the septic tank if the soil is waterlogged. Silt and mud can get into the tank if it is opened and can end up in the drainfield, reducing its drainage capability. Pumping under these conditions can cause a tank to float or ‘pop out’ of the ground, and can damage inlet and outlet pipes.
  4. If you suspect your system has been damaged, have the tank inspected and serviced by a professional. How can you tell if your system is damaged? Signs include: settling, wastewater backs up into household drains, the soil in the drainfield remains soggy and never fully drains, a foul odor persists around the tank and drainfield.
  5. Keep rainwater drainage systems away from the septic drainfield. As a preventive measure, make sure that water from roof gutters doesn’t drain towards or into your septic drainfield. This adds an additional source of water that the drainfield has to process.
  6. Have your private well water tested if your septic system or well were flooded or damaged in any way. Your well water may not be safe to drink or use for household purposes (making ice, cooking, brushing teeth or bathing). You need to have it tested by the Health Department or other certified laboratory for total coliform bacteria and coli to ensure it is safe to use.

For more information on septic system maintenance after flooding, go to:

More information on having your well water tested can be found at:

More Information on conventional and advanced treatment septic systems can be found on the UF/IFAS Septic System website

Meet the Author: Carrie Stevenson

Meet the Author: Carrie Stevenson

Carrie Stevenson is the Coastal Sustainability Agent for the UF/IFAS Escambia County Extension Office, and has been with the organization almost 17 years.  Her educational outreach programs focus on living sustainably within a vulnerable coastal ecosystem. She helps clientele better understand how to protect and preserve local ecosystems and water resources, wisely use our abundant rainfall and sunlight, and prepare and mitigate for flooding, coastal storms and climate impacts.

Growing up an avid reader and science junkie, a young Carrie aspired to find a career that allowed her to “be outdoors and wear jeans,” and in college sought to become a science writer. When National Geographic didn’t come calling, she found a position as a field-based environmental specialist with the Florida Department of Environmental Protection. There, she handled compliance and enforcement cases related to stormwater and wetlands, spending days tromping through the swamps, wet prairies, and newly build subdivisions of northwest Florida. After joining UF IFAS Extension, she spent 6 years as a Florida Yards & Neighborhoods Agent before switching to Coastal Sustainability. Her expertise and articles focus on climate issues, stormwater, hurricanes, native plants, and wetlands.

A lifelong outdoors enthusiast, she enjoys biking, standup paddleboarding, and traveling to national parks with her family. She also has many favorite international outdoor experiences, ranging from hiking glaciers in Canada to snorkeling coral reefs in Belize and watching elephants drink from a South African river. A native of Mississippi, Carrie has lived with her husband in Pensacola since 1999. Carrie earned her master’s degree in Biology/Coastal Zone Studies from the University of West Florida in Pensacola and an undergraduate degree in Marine Science from Samford University (Birmingham, Alabama). She is the proud mom of an Eagle Scout and leads her daughter’s Girl Scout troop. She is a Fellow in the Natural Resources Leadership Institute (NRLI), past president of the Florida Association of Natural Resource Extension Professionals (FANREP), and member of IMPACT 100 Pensacola Bay.

Climate Change and Future Hurricanes

Climate Change and Future Hurricanes

A living shoreline project was implemented on this bay in Santa Rosa County to try and prevent further erosion. Photo credit: Carrie Stevenson, UF IFAS Extension

We have reached that time of year when the Atlantic starts cranking out storms, and they will continue to roll out as the dog days of summer progress. Over the last decade, many experts have speculated on how climate change and sea level rise might impact hurricanes in the Gulf of Mexico. Two big issues are coastal erosion and flooding from storm surge and rainfall.

Those who live on the water or frequently visit area shorelines have probably noticed coastal erosion. While a natural part of a coastal ecosystem–and often exacerbated by heavy boat traffic–rising seas can also cause erosion. Sea level rise moves water slowly inland and washes away the roots of grasses and trees that once held the shoreline in place. Buildings and roads close to the water are impacted as well, with “sunny day flooding” on the roads and under pilings in many south Florida cities where water has moved in to stay. Large scale beach renourishment projects, living shorelines, and even road relocations (like the one at Ft. Pickens on Pensacola Beach) are all ways that local officials and property owners can respond to rising seas. However, these efforts always come with a big price tag. When that “line in the sand” is drawn beyond government and household budgets, there will come a point when we can no longer support protection of highly vulnerable coastal infrastructure. The closer a building is physically located to the water (whether built there intentionally or reached by rising seas), the greater the likelihood a hurricane will cause flooding damage from dangerous storm surge. Storm surge and heavy flooding cause 75% of the deaths in any given hurricane.

During a recent webinar, the appropriately named Dr. Chris Landsea of the National Hurricane Center answered several frequently asked questions on the impacts of global warming on hurricanes. Some of the predictions are surprising based on assumptions that have been put out in the media. He made a disclaimer that these are his predictions based on years of expertise and data analysis, and not an official proclamation by the National Hurricane Center. Following are a few of the points he made during his talk.

Dr. Chris Landsea of the National Hurricane Center recently met with floodplain managers around the Gulf Coast to discuss hurricanes.

Question: Will hurricanes get stronger based on increased temperatures?

Answer: The world average temperature has gone up 1.5 degrees Fahrenheit in the past 100 years. Based on data and computer modeling from the NOAA Geophysics Lab, typical hurricane wind intensity will increase slightly, by 3%. In this example, a storm with 100 mph average winds would be 103 mph by the end of the 21st century.

Question: Will we experience more tropical storms as the climate changes?

Answer: Dr. Landsea does not expect more tropical storms as the temperature increases. In fact, frequency may drop very slightly. While there may be more heat energy for hurricanes to feed on, the surrounding conditions will make it tougher for a storm to form. Those conditions may be atmospheric or include a vertical wind shear that tears up the storm.

Question: How will global warming affect rainfall during hurricanes?

Answer: Models and recent experience show that rainfall will increase by 10-20% during tropical storms. Global warming increases the amount of moisture in the atmosphere, and a hurricane can recycle this water into a constant loop of rainfall. Hurricane Harvey in Texas was one example of this situation, during which nearly 8 feet of rainfall fell, flooding neighborhoods. One of the aphorisms of climate change is “wet places get wetter, and dry places get drier.”

Dr. Landsea’s full presentation can be found online here, if you are interested in learning more. Keep in mind that these predictions can change based on land use, atmospheric carbon levels, and human practice change. For more on the work UF IFAS is doing on climate, visit this Florida Sea Grant Climate page.

“Doing Something” in Dog Days

“Doing Something” in Dog Days

Canis major constallation

Dog Star nights Astro Bob

The “Dog Days” are the hottest, muggiest days of summer.  In the northern hemisphere, they usually fall between early July and early September. The actual dates vary greatly from region to region, depending on latitude and climate. In Northwest Florida, the first weeks of August are usually the worst.  So, get out before it gets hotter.

In ancient times, when the night sky was not obscured by artificial lights, the Romans used the stars to keep track of the seasons. The brightest constellation, Canis Major (Large Dog), includes the “dog star”, Sirius. In the summer, Sirius used to rise and set with the sun, leading the ancient Romans to believe that it added heat to the sun. Although the period between July 3 and August 11 is typically the warmest period of the summer, the heat is not due to the added radiation from a far-away star, regardless of its brightness. The heat of summer is a direct result of the earth’s tilt.

Life is so uncertain right now, so, most people are spending less time doing group recreation outside.  But, many people are looking to get outside  Spending time outdoors this time of year is uncomfortable, potentially dangerous, due to the intense heat. So, limit the time you spend in nature and always take water with you. But, if you are looking for some outdoor options that will still allow you to social distance,

try local trails and parks. Some of them even allow your dog.  Here are a few websites to review the options: https://floridahikes.com/northwest-florida  and https://www.waltonoutdoors.com/all-the-parks-in-walton-county-florida/northwest-florida-area-parks/  Be sure to check if they are allowing visits, especially those that are connected to enclosed spaces.

Other options may include zoos and aquariums: www.tripadvisor.com/Attractions-g1438845-Activities-c48-Florida_Panhandle_Florida.html

Or maybe just wander around some local plant nurseries:

Migration, Adaptation, and Mitigation

Migration, Adaptation, and Mitigation

The indigenous people of Alaska have long adapted to freezing winters by relying on local wildlife for warm clothing. Photo credit: Carrie Stevenson, UF IFAS Extension

Human beings are an incredibly adaptable species. For countless generations, our ancestors have migrated to the far reaches of the planet to find food and territory. The Inuit people of Alaska adapted to months of freezing weather and darkness by developing techniques for harvesting fish through the ice and making furs from local wildlife. Meanwhile in the remote Andaman Islands, tribal people still subsist on fruit from the prolific rain forest and spearfishing in the Bay of Bengal.

Wildlife have behaved similarly throughout history. Before much of the United States was developed and crisscrossed with roads, large herds of bison grazed the entire mid and mountain west. Until the mid 1960’s, the upper Midwest and east coast experienced a tree-based squirrel migration of millions. Overhunting also impacted both of these species. According to the National Wildlife Foundation, monarch butterflies migrating for the winter from the United States to Mexico were down 15% last year due to hurricanes, warmer fall temperatures, and a lack of food sources along their routes. Overall, monarch numbers are down 90% from a peak population 20 years ago.

Worldwide, mangrove trees are moving from warmer climates into temperate habitats as climate changes. Photo credit: Carrie Stevenson, UF IFAS Extension

Recent changes in climate are also becoming a  factor for human and wildlife behavior. I find myself “migrating” into the air conditioning more often in these dog days of August as 110°+ heat indices bear down. The European heat wave this summer resulted in record-breaking temperatures and at least 8 deaths. Many European countries have never needed air conditioning, so homes, public transportation, and vehicles provide no relief from the sweltering heat. Wildlife, by contrast, cannot move indoors.  As the planet warms, some wildlife living in temperate regions may move because their homelands slowly turn subtropical. When this happens, history shows us that humans either “persecute, protect, or ignore” new species, which may result in great success or the downfall of species seeking new habitat.  In addition, biologists have been observing and expecting many tropical species of plants and animals to expand into new, warmer territories, as formerly cold climates heat up and become more suitable for particular species to thrive. Mangroves, for example, are migrating beyond the equator worldwide, while the National Oceanic and Atmospheric Administration (NOAA) Arctic report card has shown that the melting of polar ice caps has literally broken up polar bear habitat, along with reducing populations of grazing herds of caribou and reindeer.

Keep in mind that neither one hot summer nor one cold winter define the pace of climate change. The issue at hand is the long-term change. We find ourselves, in August 2019, having just experienced the hottest July (globally) on record since worldwide recordkeeping began in 1880. Some may see this as a fluke, until we consider that NOAA and NASA data show that 17 of the 18 warmest years have occurred since 2001. The patterns are changing—and as always, we humans must adapt. It is important that our adaptation includes mitigation measures, which can range from reducing energy use to planting more trees. To learn more about changes in worldwide climate and what you can do to make a difference, visit the NOAA site https://www.climate.gov/