Rogue waves

For as long as sailors have set out to sea, they’ve told stories of huge waves that strike unexpectedly. Not just in harbors, but out at sea. Tsunamis are well documented, but they aren’t large at sea. For many years, scientists dismissed these stories of huge waves that come out of nowhere as tall tales.

But with video and modern scientific instruments scientists have been able to confirm their existence. The first documented rogue wave occurred at the Daupner platform in the North Sea. When the average waves in the area were 39ft high, this one was 84 feet high! In 2000, a British research ship sailing west of Scotland measured the largest open ocean waves ever recorded by instruments. At least one wave reached a height of 91 ft.

Discovery Channel has a tv show called Deadliest Catch. In order to film the show, cameras are running on several crab fishing boats for weeks at a time. One of the cameras caught a rogue wave as it hit one of the crabbing boats.


Scientists aren’t certain exactly what causes these huge waves but they have several hypotheses. As time goes by and more research is done, hopefully this question will be answered.

The Wikipedia entry on rogue waves

Late Post

I want to apologize for today's post being so late. I write each week's posts over the weekends and post them in the morning each day before my baby wakes up. This morning she woke up at 4:30 am.

In honor of this, here's a song by the Arrogant Worms (yes, they're a real band) called "Baby Poo."

Swells

Swells are wind waves that have a very long wave length. They are often made by storms in the tropics, and then travel for hundreds or thousands of miles across the ocean. They are often, but not always, larger than the waves around them. If you’ve ever been on a large boat or a ship and that long, slow pitching, it was swells. Surfers often track them to catch the best waves.

Waves basically travel until they hit land. At 60 degrees south latitude, there is no land. The ocean stretches around the entire planet. Not surprisingly, this is where some of the largest swell waves are found. These seas are very tough and take experienced sailors to make it through them. A line from a sailing song goes "And as we wallop around Cape Horn you'll wish to God you'd never been born" (Cape Horn is the southernmost tip of South America).

The video below, taken in Wellington, New Zealand, is an excellent example. If you don’t like Rammstein (loud German industrial music) you may want to turn your speakers down.

Wind waves

Most ocean waves are caused by the wind. A gentle breeze blowing over a short distance will create tiny little ripples. But even a moderate wind blowing over a long distance can create large waves. Once they start, waves will travel for hundreds or even thousands of miles.

Waves move as long, low ridges out at sea, with most of the wave below the surface (remember the post about tsunamis?) It’s not until they reach the shallows near shore that they are forced up by the ocean bottom.



As the wave is forced higher and higher, the water on the bottom is slowed down as it drags across the ground. The water on top is still traveling at the same speed, so eventually it topples over. This is what causes the breakers you see at a beach.

Surprisingly, very little water is actually carried in a wave. As long as the wave hasn’t reached the line of breakers, the water really just moves in a circle. These circles are large at the surface and get smaller and smaller as you get deeper.



In some places, if the waves are large enough, you can get a spectacular show. This is Blowing Rocks Preserve on Jupiter Island near the town of Jupiter on the east coast of Florida. On a calm day it’s just a pretty place. The only unusual thing is the presence of large limestone rocks. But when the wind blows hard enough to make large waves, they break on the rocks and send spray high into the air in a show you won’t see anywhere else. It's well worth a visit.

Tsunamis

THESE are the waves that I was taught to call ‘tidal waves.’ In reality, they are seismic waves, caused by some movement of the Earth, such as earthquakes or landslides.

Out in the ocean they travel deep in the water. It’s only when they reach shallow water that they start to rise up. The Japanese word ‘tsunami’ means ‘harbor wave’ because fishermen out to sea wouldn’t notice them. It seemed like the waves just appeared in the shallow harbor.

Tsunamis aren’t necessarily large. Any water wave that is caused by a seismic event is a tsunami. So the can be a few inches to several meters high. But that doesn’t mean that all of the water will come in one giant wave. Also, a little known fact is that a tsunami may start by all of the water at the beach rusing AWAY from shore. Remember that a wave has two parts – a crest that rises above the water level and a trough that is below. If the trough arrives first, the water will rush out to sea. If you ever see this happening, run to high ground immediately. A British school girl who knew saved 100 lives.

In this video of the Boxing Day tsunami, you can see several things. It starts with a fairly large wave. Then, if you look carefully, you can see the water recede. There is a single large wave, followed by more waves as the water just keeps coming.

NOAA’s website on tsunamis.

The REAL Tidal Waves

People of my age or older (I’m 39) grew up hearing about ‘tidal waves’. This is NOT an accurate name at all. Those giant waves we heard about have nothing to do with the tides. The waves we were taught about are actually tsunamis, which I’ll talk about tomorrow. But there ARE giant waves that can be called tidal waves, although they are more accurately called tidal bores.

A Tidal Bore happens when the tide pushes its way up a river. This might happen every day, such as in the Bay of Fundy, or only a few times a year on certain rivers. The tide comes in so suddenly and so powerfully that it forces its way upstream in one large wave, essentially forcing the river to flow backwards!

In Nova Scotia, Canada in the Bay of Fundy, you can raft on the tidal bore. In other places people have surfed them. But you need to be careful; even if they aren’t tall, these large waves are immensely powerful.

Surfing a tidal bore on the Amazon River



Showing the power of a tidal bore; people get swept downstream

Of Plants and Sex

You may ask yourself "What IS this yellow stuff that's covering everything?" And you may ask yourself "Why does it make me sneeze and cough?" And you may tell yourself "This is not my beautiful house."Sorry, got off track there. **grins**

Okay, back to the original post. That yellow stuff everywhere is pollen. Okay, yeah, great, but what is pollen? Well, the simple answer is that it's plant sperm.

Wait, what?! Plant sperm? Plants have sperm? Yes indeedy they do. Plants, most of them at any rate, use sexual reproduction to make more plants. No, that doesn't mean that they have sex. What it means is that plants have male reproductive cells (pollen) and female reproductive cells (eggs.) Some plants have genders and are either male or female, while other plants have both male and female parts. Most flowers are like that. They contain a pistil (the female parts that make eggs) and stamen (the male parts that make pollen).



(The pistil is made up of the stigma, the style and the ovary)

Pollen can be transferred by animals, such as bees or hummingbirds. This is a very efficient way to transfer pollen. Most of our food crops are pollinated by honey bees. Incidentally, honey bees all over the world are dying, and we don't know why. Stop and think about the effect of losing all of our bees. Now have some respect for the humble honey bee.


But other plants use a less direct method. They just release their pollen to be blown by the wind all over the place. A very tiny amount of the pollen actually lands on the pistil of another plant of the same species. The rest of the pollen lands on your car, or your home, or in your nose.




And speaking of your nose, let's talk about allergies. Allergies happen when your body overreacts to a harmless foreign substance, in this case pollen. The pollen enters your nose. If you're not allergic, the only thing that happens is that you get yellow snot. (Don't believe me? Go outside for a while, then blow your nose and look at the tissue. Told you so.) If you ARE allergic, your body decides that it's being invaded by Something Bad and goes into full battle mode.

Your nasal tissues swell, partially blocking your nose. This prevents more of the 'harmful' substance from getting in. Your nose makes more mucous. This catches any foreign substance and pushes it back out. You cough and sneeze more, which forces that nasty invader right back out. Your eyes may water, again to flush out any strange new stuff. So all of the symptoms of an allergic reaction are actually very reasonable and good. The problem is that your body is doing all of this for no good reason.



These symptoms are caused by chemicals in your body called "histamines." So when they are over reacting and you want to stop the symptoms of an allergic reaction, you take "anti-histamines."

Bet you'll never look at pollen the same way again.