The Catskills: mountains or a plateau?

The Catskill Geologists

The Mountain Eagle

Robert and Johanna Titus

One of us, Robert, once suddenly began receiving hordes of emails from the students of an eighth grade middle school class. Each message claimed that he, Robert, had made a bad blunder in referring to the Catskills as being mountains. Each of them “corrected” Robert by pointing out that the Catskills are actually a “dissected upland plateau.” Their teacher had assigned them to do this. He wanted to know how Robert would respond to having been shown to be in error. Needless to say, this was annoying. It is, however, a commonly held notion that the Catskills are, on the basis of some narrow technicalities, not a range of mountains, but a plateau that has been lifted and then eroded, or dissected, by numerous streams, hence a dissected plateau. Let’s deal with all this in today’s column.

English is a wonderful language, well suited to describe the distinctions between all sorts of ethereal concepts. Typically, it is possible to use a choice of several words to describe the same thing. The words mountain and plateau are examples. The two terms grade into each other, but are defined in the Glossary of Geology, published by the American Geophysical Society (AGI). These are thus as close to official as such definitions can get, and they give plenty of guidance and also considerable leeway in using the two words.

The AGI definition describes mountains as being, first of all, taller than hills, usually rising more than 1,000 feet above surrounding lands. Equally important, mountains have restricted summits. They have steep slopes and considerable exposed bedrock. Perhaps most importantly, they are distinctive enough to have individual names. That last point is subjective, but critical.

Plateaus do not have restricted summits; they are “comparatively” flat areas “of great extent and elevation.” A plateau’s “flat and nearly smooth surface” can be “dissected by deep valleys or canyons.” But in the end, it must have a “large part of its total surface at or near the summit level.” When we look at maps of the Catskills, we think that the valleys are so broad, and the summits so restricted that they just do not conform to the notion of a plateau.

The Catskills are composed entirely of nearly horizontal sedimentary rocks and some think that this makes them a plateau. But the AGI definition does not prohibit flat-lying strata within mountains. Nor does it does it require them in plateaus. Those horizontal strata date back to the origins of the Catskills as a great flat-topped delta.

We travel the Catskill Mountains and see so many distinctive summits. Slide Mountain meets all the standards required to be a true and distinctive mountain. So do North and South Mountains, Overlook Mountain, Windham High Peak and so many others.
When there are a number of such mountains, the AGI glossary specifies that they can be combined under a proper name heading, such as the Adirondack Mountains.

But, beyond all of the above, there is an issue of elegance. English should, as often as possible, be an elegant language. Its words should flow off the tongue smoothly, they should also read the same way. We ask you: did Rip Van Winkle sleep for 20 years in a dissected upland plateau or in the Catskill Mountains?

Climb to the top of Slide Mountain someday this summer. Gaze out all around and decide for yourself: are you standing on top of a plateau?

Contact the authors, unless you are an eighth grade teacher, at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at “thecatskillgeologist.com.”

Looking into the future

The Catskill Geologists; The Mountain Eagle, 2088

Robert and Johanna Titus

We frequently travel about in the Catskills and we are always on the lookout to find a new topic for one of our columns. One day, recently, we were approaching Mt. Utsayantha from the northeast on County Rte. 14. On the mountain’s slope, rising in front of us, we noticed a fairly nondescript mountainside feature. Take a look at the left center part of our photo. You will see what is sometimes called a niche, That is, there is a depression in the side of the mountain.

Well, “so what,” you might ask, “big deal, what is there to get excited about?” And, you would be right; this is not an especially big deal; it is just a depression in the slope. But, we are geologists, and we are writers. We are always looking for an angle. After all, we have to send off a column almost every week.

We started taking this image and projecting it into the future, of course we mean the distant geological future. What, we wondered, would happen if another ice age came along? Our niche in the mountain would soon fill up with snow. And that would initiate a sequence of very predictable events, typical of the latest chapter of an ice age.

First that niche would accumulate thicker and ever thicker amounts of snow. Then the thickening snows, under the influence of their own weight, would start compacting. The snow would be squeezed down into a material that would resemble the packed snow of a snowball. Geologists call that material neve’. But, the process would not stop there; the compacting would continue until the neve’ would harden into genuine ice.

Once enough ice accumulated in the Mt. Utsayantha niche, it would start to become dynamic. Ice can flow like a great rigid mass of water. Its flow will be very slow, but it will move. It has become a glacier, in fact it has become an Alpine glacier, at least a future Alpine glacier.

We had slowed down but now, intrigued, we pulled over, got out and stared up at our Alpine glacier. Usually we gaze into the past but this time we found ourselves looking into the distant future. We had traveled to a time when the Catskills had come to resemble the Alps of today’s Switzerland.

When will this future Switzerland descend upon the Catskills? We don’t know; we haven’t gotten any of the ice age geologists, that we know, to commit to a precise prediction. But current ice age theory argues that glaciations occur in cycles that recur about once every 100,000 years. So don’t hold your breath. It gets worse; Alpine glaciers don’t form until late in ice age chapters. After all the ice, everywhere else, has melted away then the cold mountaintops become active and Alpine glaciers form.

That happened in the past. At the end of the last ice age, Alpine Glaciers formed atop the highest peaks of the eastern Catskills. The best example that we know of are found at North Point, near North Lake Campground and to the south at Overlook Mountain. Another very fine Alpine peak is Hunter Mountain.

But why didn’t Mt. Utsayantha develop some Alpine glaciers the last time? It may be that the mountain is just not tall enough. It reaches an elevation of 3,200 feet; the others are just a bit taller. So, sadly, Mt. Utsayantha may not be tall enough the next time. But, we can dream.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at thecatskillgeologist.com.

Tetraxylopteris

The Catskill Geologists; The Mountain Eagle; July 6, 2018

Robert and Johanna Titus

Tetra-what? Are we kidding? Well, if you have been able to read this far, we commend you. Our title is a one-word mouthful, isn’t it? But, here in the Catskills, this is something of an important word. It’s the genus name for a fossil plant that lived in Gilboa about 380 million years ago, during the late Devonian time period. With a name like Tetraxylopteris it’s going to be a challenge to write about this plant, but we are pros; let’s give it a try and even attempt to explain why this is something important in our region’s fossil record.

Take a look at our photo. It was taken in the open shed outside of the Gilboa Museum. The fossil lies upon the surface of an enormous boulder, collected in the Gilboa vicinity. Being outside, you can visit it any time you wish, all year round. The plant is a very distinctive one. You can see a main stem and then branches that stick out at nearly right angles. When those branches, themselves, have their own branches, those stick out–again at 90 degree angles. This rectangularity makes the plant so easy to identify. You just became an expert, but why is it important?

Tetraxylopteris takes us back to the Devonian time period when land plants had only recently evolved and were spreading out across the landscapes of the world. This was important evolution. We are speaking of the first time appearance of forest ecology itself–now that’s important.

The plant was a true land dweller; it had tissue that served to draw water out of the ground and pass it upwards into the stem and branches. We call that vascular tissue and it has always been an important feature of all true land plants. It had a woody stem and wood was a new “idea” for plants back then. Some of the very best preserved specimens have flattened structures on their outermost branches. These are thought to be proto-leaves, not true leaves but something broad, flat and photosynthetic. It was a good evolutionary start for real leaves.

It’s that woody stem that has been regarded as a trait that links it with the gymnosperms, many of which are today’s evergreens and cone-bearing trees. Tetraxylopteris was something you might call a bush; it probably did not grow as tall as a true tree. Some paleobotanists think it grew in thickets with each bush supporting its neighbors.

It was a primitive land plant in the manner of its reproduction. It did not produce seeds; it had an organ that produced tiny reproductive structures called spores. Individual spores are single cells that spore-producing plants use. They are caught up by wind and blown around, a lot like pollen. When they fall to ground they act like seeds and grow into a new plant. That may link this plant with ferns. Ferns, too, are primitive land plants that reproduce by using spores. If you think that the pollen season is bad nowadays, it might well have been much worse during the Devonian!

By the way, that name is not as hard to say as you might think. Try saying “tetra – xi – lopp – teris.” With a little practice it rolls off the tongue. And you will feel so smart just being able to say it!

The Gilboa Museum is having a big event, the Gilboa Fest, this Sunday, July 8^th from 10:00 to 4:00. Why not come along and see their fossil plants, including Tetraxylopteris, at the same time?

Contact the authors at randjtitus@prodigy.net, Join their facebook page “The Catskill Geologist.”

THE CATSKILL GEOLOGISTS BY PROFESSORS ROBERT AND JOHANNA TITUS

Follow the Science?      

The Mountain Eagle Dec. 20 , 2024               

   The pandemic wreaked havoc all around the world. But science itself is among the many losers. Polling before the pandemic showed that 86% of American thought that scientists act in the public’s best interest. That dropped to 66% during the pandemic. Those numbers drop even more when only Republicans and/or Independents are sampled. That’s, of course, dismaying to us. We have been scientists, literally as long as we can remember. Both of us began our serious interests in science in our very early grammar school years. Neither of us can remember a time when we did not want to be scientists. We have practiced science as professionals and now, in retirement, we are popular science writers, sharing our lifetimes of work with you. We know science about as well as anyone and we are, to be sure, extremely confident in it and its practices.

Why the skepticism? Well, science and scientists have never been shy about telling people things they do not want to hear. That goes back at least as far as the 1500’s and astronomer Nicolaus Copernicus. Copernicus studied the nighttime skies, especially the planets, and determined that the earth was not the center of the universe. Our planet, and all of the others, rotated in revolutions around the sun. While his idea was “revolutionary” it was not very popular, especially with the Catholic Church. Problems for science only got more abundant as the centuries passed. Today scientists find themselves arguing against all sorts of things that are popular notions, often passionately and widely believed in.

That, quite possibly, includes things that YOU see as true and perhaps even important. Do you believe in Astrology? Do you follow your daily horoscope? If so, you are hardly alone, but science has not found the evidence to support its claims. How about clairvoyance? That too hasn’t been confirmed by proper lab experimentation. Do ghosts exist? They, after all, have sometimes been photographed. The photos are phonies. Have you seen sasquatch? It was recently reported in the town of Cairo, right behind the Dollar General. Naturally we have been watching for Sasquatch, but we have missed him so far. Can someone bend a spoon with their mind? Please! We are indeed skeptics, but scientists are supposed to be skeptics – always.

For the two of us these things sometimes strike close to home. Are you a young earth creationist? There are plenty of them. Well, sorry; we are both evolutionary biologists and several peer-reviewed articles about evolution, published in respectable science journals, have come out of our home. Do you believe in Noah’s Flood? If it actually happened, then most of the thousand columns we have published these past 33 years are false. Everything, and we mean everything we know about biology and geology, speaks clearly of a very old planet upon which life has slowly and steadily evolved. One large problem with the acceptance of science is that so many scientists are poor, to say the least, in communicating what they do. The two of us have done as well as we can along those lines.

So, what about the most recent loss of confidence, why is that? The answer is that science demonstrates the effectiveness’ of vaccines. We know – we know; all sorts of arguments have been made against vaccines. But the science of statistics is clear: vaccinated people, definitely including the two of us, are not as commonly sickened by the diseases that they have been vaccinated against. They are not as commonly hospitalized, and they do not die as commonly as unvaccinated people. If you insist upon not being vaccinated, then go ahead. The results? Darwin could have explained them better than we can.

Contact the authors at randjtitus@prodigy.net. Join their facebook page: “The Catskill Geologist.” Read their blogs at thecatskillgeologist.com.

Crinoid Columnals

The Catskill Geologists, The Mountain Eagle Jan. 15, 2021

Robert and Johanna Titus

We have about 1,400 members of our “The Catskill Geologist” facebook page. And many of them are very remarkable people. And they often send us such interesting photos. Recently we received an especially good one from Stephanie Theado from Bovina. Stephanie found some fossils along Schoharie Creek and wondered what they were. Take a look at her photo and see what you think.

Stephanie was most impressed by the flower shape within the one to the right. But what could these strange looking fossils be? There is no intuitively obvious answer to that question. That is unless you are an experienced geologist. These are very common fossils called crinoid columnals. To help you understand all this, first we have to tell you what a crinoid is. Crinoids are alive today; most of them are found on deep water sea floors. They are animals but look a lot like flowering plants. Hence, they are commonly called sea lilies. Take a look at our second illustration.

Crinoids are members of an invertebrate group called the Echinodermata. That makes them distant cousins of starfish and sea urchins. All are characterized by a very odd trait; they all, typically, have five-fold symmetry. That’s best displayed with the five arms of starfish but look again at Stephanie’s photo. Her “flower” has five petals, so typical of all echinoderms.

Sea lilies have usually lived on the bottoms of seas. They are typically rooted to the sea floor by a structure aptly called a holdfast. At their tops are structures called crowns. Crowns have arms equipped with net-like apparatus that filter food particles out of surrounding sea water. We call such creatures filter feeders. Connecting the holdfast with the crown is a long “stem.” That stem is composed of numerous skeletal elements called columnals. Again, look at our photo and see the holdfast, stem and crown.

It’s a rare day when a paleontologist finds a whole fossil crinoid. Typically, they decay and disarticulate after death. What we do find, more than anything else, are loose columnals, just like what Stephanie found. These are very common fossils, and you should take a good look at the photo; you are likely to see these from time to time. It’s a nice thing to know what they are.

It is not likely that these fossils are native to the strata along Schoharie Creek, unless that was at the far northern end of that valley. Stephanie’s fossils were almost certainly brought to where she found them by an ice age glacier. Glaciers may have done the same where you live. So, keep an eye out for these fossils.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at “thecatskillgeologist.com.”

The art in a weathered old rock

The Catskill Geologists; The Mountain Eagle; Dec. 20, 2019

Robert and Johanna Titus

Often, the hardest part of our writing these columns is shooting the photos. We really need good illustrations of those things that interest us if we are to explain them to you. So, it might not surprise you that, from time to time, we borrow a photo from someone who is better at picture taking than we are, especially if that person is a lot better. Have you ever seen the images done by Art Murphy? Art is a professional photographer and a good friend of ours. We like his work and respect it. He is quite unusual in that he specializes in shooting pictures of fossils. As he lives in the Catskills region, that means he mostly takes photos of Devonian aged fossil invertebrates, and he is good at it. He finds just the right fossil shellfish, catches the perfect light and color, and presto; Art has created art! He runs a blog at “https://artandfossils.wordpress.com.” Every week or so he publishes a series of his recent photos and we always find them fun to view. You might give it a try.

Recently, Art departed from his norm and ran a group of photos which showed not fossils, but the chemical weathering of stratified rocks that was going on in his favorite local quarry. We were inspired to see what we could write about some of his photos and Art generously let us use them. Today’s column shows the first.

Take a look at it; what do you see? We see two colors: a lot of yellow, forming a coating across the surface of this rock and lesser amounts of bluish gray. We think the gray is the rock itself in its natural state. Art showed us around the quarry a few years ago and that’s what we saw. We were, on that day, visiting an ancient sea floor. Those sedimentary rocks had once been sandy muds on the floor of the Devonian Catskill Sea. We saw a lot of fossils in these rocks, so we know it was a sea floor that was favorable to life, specifically there was enough oxygen in the water to support invertebrate animals. But there wasn’t much more than just that. The relatively dark color indicated that there had been some limits on the oxygen contents.

And that was the proverbial rub; these dark sediments hardened to become dark rocks, and both the original sediments and, later the rocks, reflected those limited oxygen contents. Rocks or sediments, it didn’t matter; they had only ever been stable within relatively low oxygen levels – unlike those of the modern quarry floor. Quarrying had brought dark rocks to the surface and exposed them to large amounts of atmospheric oxygen – molecular O_2. That’s when chemical weathering began. The air’s moisture and oxygen “attacked” the iron bearing minerals in the rocks in a chemical process geologists call oxidation. Iron, in the rock, was converted into a mineral that is called limonite, and limonite is the yellow part of Art’s photo

Limonite is an unusual mineral. It does not have a crystalline structure; it might be described as a mishmash of iron, oxygen and hydrogen atoms. Limonite has a common name; it can be called “rust.” When the oxygen of water attacks manmade iron artifacts it is said to rust them away. In this case, the rock will never rust away. Instead, a thin yellow coating will form on the surface of the rock. Oxygen has turned the iron in the rock into limonite. Then it will sit and wait, perhaps years and decades, until just the right artist comes along.

You have learned just a little science today; that wasn’t hard, was it?

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at thecatskillgeologist.com.”

A bit about us

The Catskill Geologists; The Mountain Eagle, 2017

Robert and Johanna Titus

Are you, like us, a fan of those murder mysteries you see every week on the local PBS station? We watch them all: Miss Fisher’s Murders, Father Brown, Murders in Paradise: you name them; we watch them. Most people have long wondered how it is that those detectives run into murders as often as they do. Every week, like clockwork, somebody is conveniently murdered right under their noses. It would seem that murderers follow them around, doesn’t it?

Well, that part of it does not bother the two of us very much. You see, our lives are a lot like that. No, we don’t have murderers following us around, but wherever we go there is almost always some gem of a geological story – right there in front of us. There has to be; we write these columns week after week.

Think about it the next few days as you go about your routines. You do the same things we do. You drive down the highway and pass by outcroppings of rock. So do we, except that we often stop, get out and take a look. We know that an outcrop might very well have an interesting story to tell. And, with a little luck – presto – we have a column to publish.

You, like us, are likely to find yourself in some substantial Catskills valley. Our landscapes are full of valleys. Well, it is different for us. Almost any valley, here in the Catskills, was likely to have been filled with a glacier back during the Ice Age. And that is where our imaginations kick in. It’s one thing to see a glacier filling some local valley, but we start imagining it at different times of the day and different stages of the Ice Age. Why just look at a glacier when you can see one during a full moon at midnight. We see the moonlight shining down on the ice and creating a shimmering silver glow. We can always wait until the climate warms up and that glacier starts melting. That’s when raging, forming, pounding thundering torrents of meltwater pass by us – or pass beneath us – or – worst of all – over us!

Each of those outcrops offers a different journey into the past. Here in the Catskills, a lot of them are composed of river sandstones. We stand in front of those, hold out our hands and feel the river currents. We see the fish that lived in those streams. We leave those rivers and climb up their banks. Soon we are wandering through forests that lived here in the Catskills about 380 million years ago. These are as real to us as modern streams and forests are to you.

Other bedrock includes limestones. Those almost always take us back to ancient shallow tropical seas. We have been to today’s Florida and the Bahamas, so we know what kinds of places produce limestones. We see grey bedrock, but we experience aqua-colored waters with colorful seaweeds and animal life.

Those television detectives solve their mysteries week after week and so do we. Our explorations take us to ancient landscapes and even older seascapes, but we cannot truly “experience” them until we have done some detective work. We are scientists and we are writing about our science. All scientists have always been puzzle solvers. Our columns are just special types of puzzles. So, come back next week and read our next column. Try to understand that you are following along as two scientists do their work right here in your Catskills.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist” Or read their blog “thecatskillgeologist.com”

A scenic landscape

The Catskill Geologists; The Mountain Eagle; Dec. 12, 2019

Robert and Johanna Titus

Some landscapes are more picturesque than others. Our Catskills are truly blessed when it comes to scenery. For the two of us, however, it can be the geological past that makes a landscape even more remarkable than you might at first think. You travel south on Rte. 145 from Middleburgh and enter Durham. Watch for Stone Bridge Road on the left and turn onto it. You pass an ancient graveyard with fine old stone tombstones and beyond that is a very nice rolling farmland. Do you enjoy walking through such a cemetery, looking at finely made tombstones? Well. this a place for you. But, for us, it was that farm field that caught our eyes. What’s there? Well take a good look at our first photo.

We call this a rolling landscape and that is certainly true. There are so many sinuous curves here; the field gently rolls up and down sort of like the waters of  an old Chinese print of a great stormy sea. There is hardly a geologist anywhere who would not look at this without seeing into its ice age past. We would like you to develop this sort of skill, so, we have a little explaining to do. Those sinuous ups and downs have names. The ups are called kames the downs are called kettles. They formed very late in the Ice Age. At that time this landscape was still thawing out. Many locations had large masses of ice buried in the earth here. How large? Well, many were the size of houses. That’ was a lot of ice in each of these. Most are thought to have been buried in earth. That earth acted as insulation and so each mass of ice took a long period of time to thaw out. Some suggest that the melting took centuries. As the thawing continued, a lot of that overlying earth collapsed upon the melting ice. That resulted in those sinuous kettles. The earth in between was left behind as those sinuous kames. There was more; we drove a short distance down Stone Bridge Road and there was a fine small shallow pool of water. See our second photo. That water fills a particularly deep kettle; it is called a kettle pond.

We are experienced geologists and it took but seconds for us to recognize the big picture here. We saw that we were looking at what is called a glacial moraine. That is a heap of earth that was bulldozed into place by an advancing glacier. That glacier advanced as far as it would– so long as the climate was cooling – bulldozing morainal sediments all along its front. Masses of ice came to be incorporated into these earths. Then the climate warmed up and the ice began its retreat. This new landscape began its thawing out. Those blocks of ice took the longest, but they did melt and that produced those kettles. As the kettles formed so too did the kames.

We stood along the road and looked down the valley and then returned to that ice age past. We viewed a still largely frozen landscape. We saw all those kames and kettles. A few of the kettles still had large masses of dirty ice rising out of them. We craned our necks and looked all the way down the valley as far as we could see. There, in the far distance, we saw a great glacier. It rose high above the valley floor and stretched across the entire valley width. Its front was badly fractured and enormous volumes of meltwater were pouring out of each fracture. This was truly a scenic landscape, perhaps more so to us than to others.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

Death of a Farm?

The Catskill Geologists; The Mountain Eagle; Dec. 6, 2019

Robert and Johanna Titus

Did you read about Hull-O-Farms in the New York Times recently (Nov. 28, 2019)? The article was on the front page, and it was actually above the fold. That’s something that doesn’t happen to a Greene County farm very often. We were intrigued so we read the article with real interest. Turns out there was some geology in the story so here is our version — above the fold on Page D-1 of the Mountain Eagle!

Hull-O-Farms is a 260-acre farm on Cochrane Road in Durham. It has been farmed by seven generations of the Hull family. That makes it one of the oldest one-family farms in America. Sadly, no member of the eighth generation is able to take over from Frank and Sherry Hull. They have had success running it as a farm-stay bed and breakfast, but they are just getting too old for all the hard-work and they may well have to sell their land for development. There is just a little hope; efforts are underway trying to find young would-be farmers and match them with threatened but available farmlands. But it is doubtful that this will happen. It’s a sad story being repeated all across the country. Family farms are disappearing every day and that was the whole point of the Times story.

But we wondered if there was a geological story behind the story, so we did a little research. The was a brief mention in the Times article that the soils were more than just a bit muddy. We started there. We got out our Greene County soil survey and looked up that stretch of land on its map. We found that most the Hull farmland is blanketed in soils called the Burdett silt loam. And, indeed, they are clay-rich and damp., and they are good for pasturing dairy cattle but the economics of that have become weak. They can be farmed but they are only rated as “moderately suited” for cultivated crops. We wondered why and read on. It turns out that the Burdett soils have been developed upon what is called glacial till. Till is a vaguely defined word in the lexicons of geology but it is, in this case, a thin layer of earth left behind by the melting of a dirty sheet of ice. We called a similar nearby deposit a ground moraine in our July 26^th, column.

Well. this till/ground moraine was developed upon some Devonian aged bedrock which was essentially a shale. So now we had some more researching to do. We got out our copy of the New York State Museum’ geologic map. It looks like Hull-O-Farms lies upon some marine shales called the Manorkill Formation. These shales were deposited as mud on the bottom of the Devonian Catskill Sea about 380 million years ago. Now they are turning back into muds, the muds of the Burdett soils.

So, to sum it all up. The Devonian seas, that were once here, deposited those marine shales. Those rocks sat there for about 380 million years until the Ice Age when glaciers came along. The glaciers gouged out the shales and turned them into the tills that made ground moraines. During the 14,000 years that have passed by since the Ice Age those glacial deposits have been turned into the Burdett soils. The Hulls came along in the late 1700’s and began the farm. Seven generations later that is coming to an end. There is so much history here; the New York Times story missed nearly all of it.

As of Oct. 30, 2024 they are still in business!

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Learn more about Hull-O-Farms at www.hull-o.com.

Cold snaps?

The Catskill Geologists; The Mountain Eagle. Nov. 18, 2019

Robert and Johanna Titus

We have seen some pretty cold weather lately. November 12th and 13^th witnessed what was called “historically cold weather.” Forecasters warned that this may be repeated, perhaps many times this winter. Specifically, they predict that cycles of cold Jet Stream air masses will pass slowly across North America during this year’s winter. Each pass is expected to bring similar “cold snaps.” Each cold episode can be an alarming event. How many times have you heard people say, “What happened to climate warming?” That’ a fair question, so we would like to give answering it a try in today’s column. Our argument is that there is, indeed, an explanation for this weather, and it may actually be that has been caused because of, not despite global warming. Obviously, we have a lot of explaining to do.

Let’s begin with a short overview of what the jet stream is. In North America the jet stream is a massive, high-altitude eastward flow of air lying at the boundary the Arctic and the Mid Latitudes. The stream typically undulates up and down through broadly prominent ridges and troughs. See our first illustration. It’s the temperature difference between the cold Arctic and warmer Mid Latitudes that drives the jet stream; the greater the difference, the faster the jet stream. That difference drives the cold troughs and warmer ridges across America. That brings a lot of weather to us, especially as it did in what came to be called “Novembruary.”

                    Normal jet stream, Illustration courtesy of Wikimedia Commons.

In recent decades there has been a consistent and pronounced warming of Arctic realm climates. That’s something we remember that climate scientists predicted at least 30 years ago. At the same time the mid latitudes have only warmed a little, so the differences have been greatly reduced. That has, as would be expected, slowed down the movements of those ridges and troughs. What results is a lot like what happens to auto traffic when it is slowed down. The cars behind catch up with those in front. The ridges and troughs become slower and more closely spaced. But there is more; in order to keep all those air masses moving, both the ridges and troughs must become more expansive. See how, in our second illustration the ridges and troughs are so accentuated. We call this a higher amplitude.

High amplitude jet stream. Courtesy US Geologic Survey

Each trough is a mass of slow moving very cold weather. Just what we saw in middle November. Each trough becomes at least a few days of very cold weather. Each expands far to the south and spreads across a vast expanse of our continent. We all, especially in the south, find this most unsettling. But, as you can see, it’s all a very explainable phenomenon. We think it is something that you should understand.

In the end we are hoping that you will pay more attention to the jet stream part of your local weather forecasts and have a better understanding of what they have to tell.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”