Freezing Rain, Sleet.
Ice and Climate Change
Ice "created" a bird with ice. In the last couple of days, I got a lesson in freezing rain, sleet and ice. All three phases are not pleasant, but I had my safe observation post at the bay window in the house. It all started with temperatures a little above freezing. We had a slight drizzle and everything looked kind of wet. What I did not know was that the temperature had fallen almost ten degrees and the wet surface had changed into a thin coating of ice. And this coating was growing with every raindrop!
I thought about what was happening. The liquid raindrops had arrived in a layer of fog well above the ground. On their way to the surface they came into a layer of freezing air above the ground. Unfortunately the freezing air was a rather thin layer, so the raindrops had no time to freeze before hitting the surface. On impact though, they froze immediately and we had as a result, a very slippery driveway. On asphalt, this is known as ‘black ice’, and is very treacherous. The reason is that this very thin layer of ice is clear and is seen to just be wet black asphalt, not a deadly sheet of intractable ice. In the glare of oncoming headlights, it is nearly impossible to see the difference, so drivers go too fast and lose traction. This is why newscasts emphasize it so much.
Sleet forms when the raindrops hit a thicker layer of freezing air so that they have time to freeze before hitting the ground. Both freezing rain and sleet are dangerous not only for driving but also for walking. In weather like that I will not leave the house without my hiking stick. Ice is more treacherous than loose ground.
As both the freezing rain, as well as the sleet, will settle on branches and phone and power lines, a lot of weight will be added and the possibility of snapping without warning is always there. I could see how the branches of our pine trees moved closer and closer to the ground, almost touching it. In early Fall, storms like these can be particularly damaging to trees if they have not yet shed their leaves. The surface area of a fully leafed tree is many times greater than a bare one. So an early Fall ice storm will greatly increase the tonnage of weight on the limbs and roots.
As both the freezing rain, as well as the sleet, will settle on branches and phone and power lines, a lot of weight will be added and the possibility of snapping without warning is always there. I could see how the branches of our pine trees moved closer and closer to the ground, almost touching it. In early Fall, storms like these can be particularly damaging to trees if they have not yet shed their leaves. The surface area of a fully leafed tree is many times greater than a bare one. So an early Fall ice storm will greatly increase the tonnage of weight on the limbs and roots.
Be particularly wary of any suspicious trees close to your house under these conditions. The chances of one of them toppling has been increased exponentially, particularly if winds accompany the storm as it leaves the area. A fully leafed tree is like a sail. Think of a sailboat under full sail, being bent over by the wind almost to capsizing. That may very well be your tree in the backyard. Add the tonnage of ice or snow to the equation, and the root system may not have grown sufficiently robust to handle the unusual loads of wind combined with extra swaying weight.
Extra attention should be paid to evergreens planted within striking distance of the house for this reason. They are particularly susceptible to snow loading and wind, precisely because they don’t shed their leaves in the Fall. One might think that they would have evolved growing patterns to avoid this from happening over millennia, but realize that this doesn’t necessarily apply here. Most of the plantings that we have around us are cultivars from all around the world. They didn’t probably evolve under your local conditions, and may not be suitable for these conditions. But they look good, so we plant them. If you have evergreens around the home, they need to be maintained so that wind can pass through them and unstable limbs are removed before they cause a problem (see also post of April 2018 “The fork in the tree”).
Extra attention should be paid to evergreens planted within striking distance of the house for this reason. They are particularly susceptible to snow loading and wind, precisely because they don’t shed their leaves in the Fall. One might think that they would have evolved growing patterns to avoid this from happening over millennia, but realize that this doesn’t necessarily apply here. Most of the plantings that we have around us are cultivars from all around the world. They didn’t probably evolve under your local conditions, and may not be suitable for these conditions. But they look good, so we plant them. If you have evergreens around the home, they need to be maintained so that wind can pass through them and unstable limbs are removed before they cause a problem (see also post of April 2018 “The fork in the tree”).
Black Ice Of course, you can measure how thick the ice is, but I never did. It is slippery with 1 millimeter or 5 millimeter of ice. I realize though, that just a thin coating of ice might be broken easily with a car, but don’t count on it. If you experience ice and do measure it, you can report it to the National Weather Service: https://inws.ncep.noaa.gov/report/index.html. They appreciate the data.
“Ah, well this information is fleeting and unimportant”, you might be saying to yourself. But it is not! Fortunately we are discovering new ways to reveal the permanent record of climate and weather all over this planet. As we have been developing new techniques to discover how weather and climate have changed over time, we are combining data from several different scientific disciplines. One of these is research into “ice cores” and what story they can tell us about our Earth. They hold a record of what our planet was like hundreds of thousands of years ago.
Scientists take ice core samples from inside the polar ice sheets in Greenland and Antarctica, often a mile deep, and some other ice caps and mountain glaciers. They compare those different ice cores and come to a well founded picture of the Earth’s climate at a particular point in our Earth’s history. In those core samples you also find traces of dust, ash, pollen and traces of sea salts. Even trapped bubbles of air can tell us the levels of greenhouse gases during ancient times. Comparing everything, scientists can get a good idea of what was going on in parts of our planet.
Scientists are trying to find a pattern in those cores and how the Earth’s location in its orbit around the sun is reflected in the ice cores. Our planet’s orbit around the sun is not static and unchanging. It is eccentric and changes about every 100,000 years. Three different orbital characteristics (eccentricity- the orbital shape, tilt- of the rotational axis relative to the sun which gives us our annual seasons, and precession- relative change in axis orientation) have profound effects on our climate. These factors probably account for our repeating ice ages.
Ice Core with layers like tree rings. These paleoclimatologists are trying to create climate models by looking at past models and perhaps project our climate with new models in the centuries to come. Afterall, our fears about the human impact on global climate change notwithstanding, we already know that our climate has swung wildly between extremes in the past. The planet has swung from ‘snowball earth’- an epoch in our planet’s history when the entire globe was covered in ice and snow, through periods where tropical conditions extended as far north as Canada, and at least a half dozen major ice ages, when glaciers over two miles thick bulldozed their way over most of of the Americas, Europe and Asia (See our post of March 2016 about “Snow as Molasses”).
The oldest ice core is from Antarctica and is 800,000 years old. Each layer of ice is slightly different from the year before. You just count them like rings inside a tree. They hold treasure troves of data like volcanic ash, pollen, dust and microorganisms, from which we can deduce the flora and fauna alive at the time.
Like the study of tree rings- which is known as dendrochronology, we can now accurately measure ambient sunshine, rainfall and temperatures going back a couple thousand years in some areas. It can even inform us in some cases of the exact dates of construction of human settlements in places where our ancestors built communities, or where natural events or catastrophes buried and preserved forests.
Like the study of tree rings- which is known as dendrochronology, we can now accurately measure ambient sunshine, rainfall and temperatures going back a couple thousand years in some areas. It can even inform us in some cases of the exact dates of construction of human settlements in places where our ancestors built communities, or where natural events or catastrophes buried and preserved forests.
Cypress Forest Hurricanes are just one natural event that helps illuminate our climatic past. In 2004, hurricane Ivan battered the gulf coast with record breaking waves as high as 98 feet. They uncovered a buried 60,000 year old cypress forest miles off the current Alabama seashore under sixty feet of water (https://www.al.com/news/mobile/2017/06/underwater_forest_discovered_alabama.html). Cypress forests no longer grow in that region as they need cooler weather. Scientists studying the forest were able to show that sea levels have risen in the past high enough to push the shorelines as far as 120 miles further inland north into Alabama, and fallen up to 400 feet lower than today, during the peak of the last ice age. Today’s coastal islands were terrestrial mountains towering over forested valleys where our bays are today. In 2012, hurricane Sandy also uncovered a coastal mangrove forest miles off the Carolinas in what now is 40 feet of water and dated to around 400 years ago.
Sunken City in the Golf of Khambhat But these are not the only examples of scientific evidence that for years has shown that sea levels have risen and fallen dramatically throughout history. There is abundant archaeological and anthropological evidence as well.
In just the fields of anthropology and genetic analysis, there is data that convincingly shows that human migrations out of Africa and eventually across the entire globe, were largely dependent on climate changes and falling and rising sea levels. Today we believe that humans only migrated for the first time to the Americas around 12,000- 15,000 years ago over the Bering Sea land bridge from Asia, when sea levels were low enough that there was land to cross over. The sea levels have been rising ever since.
Archeological data records submerged neolithic structures all over the globe, that have been inundated by rising seas. There are examples like:
In just the fields of anthropology and genetic analysis, there is data that convincingly shows that human migrations out of Africa and eventually across the entire globe, were largely dependent on climate changes and falling and rising sea levels. Today we believe that humans only migrated for the first time to the Americas around 12,000- 15,000 years ago over the Bering Sea land bridge from Asia, when sea levels were low enough that there was land to cross over. The sea levels have been rising ever since.
Archeological data records submerged neolithic structures all over the globe, that have been inundated by rising seas. There are examples like:
- The Sea of Galilee in 2013, as reported by CNN 4/23/13, a stone structure 30 feet below sea level, perhaps 2,000- 12,000 years old, constructed by 60,000 tons of stones, appearing to be man-made
- In the Khambhat Gulf on the western shore of India, the India Oceanic Institute, conducting a 2001 pollution study found the remains of a 5 sq/mile city constructed along ancient river channels and now submerged under 170 feet of water and estimated to have been inundated 9,000 years ago
- In 1987 off Yonaguni Island, Japan, scuba divers discovered cut and shaped monumental stone structures 60- 100 feet underwater, believed to be submerged since the retreat of the last ice age.
These are human settlements constructed of stone well below sea levels of today. We just aren’t discussing or investing money into researching them. Don’t forget, it wasn’t until the invention- in our lifetime, of scuba gear and new technologies like side-scanning sonar, that we even knew these sites existed! So there is much work to be done that is begging for financing. We just don’t know what these sites constructed by humans can tell us.
So we started here by observing the freezing rain we are now experiencing and how nature works and affects us, and ended up discussing global climate change. If you think that the rain and ice today are no longer important after they evaporate away, I hope you realize that they are. Our weather today will inform our future understanding of our climate.
So we started here by observing the freezing rain we are now experiencing and how nature works and affects us, and ended up discussing global climate change. If you think that the rain and ice today are no longer important after they evaporate away, I hope you realize that they are. Our weather today will inform our future understanding of our climate.
It would appear that we like to view the world through a straw, failing to see the whole landscape. Sometimes I’m reminded of an old proverb about five blind men describing an elephant. They are arrayed around the elephant so that one is standing by the elephant’s trunk. Another stands next to the side of the elephant. The next is located by the elephant’s leg. The next is standing by its tail, and the last sits below the creature’s belly. The king instructs them all, under pain of death, to accurately describe this new present that he has received from afar. ‘Oh master’, the first one entones, reaching out and feeling the trunk, ’you have received a gift of an immense python, capable of wreaking great harm on your enemies’. The next, touching the elephant’s side, declares ‘Oh great one, you now possess a creature of colossal height, which will dwarf your opponent’s dogs of war’. The third man feels the elephant’s leg and cries out, ‘My chief, you now have an animal as strong and tall as our largest trees, upon which you can build your empire’. The fourth blind man reaches out and feels the elephant’s tail, declaring ‘Father, you possess a small viper which has great lethality’. The last man, sitting under the elephant’s belly shouts out ‘Your highness, I have above me a gigantic bird of prey that will swoop down and crush your enemies’.
Angry because these five blind mystics were clearly wrong, the king had them all put to the sword. Often, I feel we are all like these blind men.
Angry because these five blind mystics were clearly wrong, the king had them all put to the sword. Often, I feel we are all like these blind men.
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