Category Archives: Weather

After the snow

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If you watched the news Wednesday, you probably already know we had snow in Georgia. Atlanta was paralyzed. If you read my previous post, you also know that there were a lot of impassable roads in Alabama Tuesday night. Wednesday morning dawned clear and very cold. We had three inches of snow and 10 F. I don’t think Rome’s traffic situation was anything like Atlanta’s, but we had no reason to leave home Wednesday anyway.

I did take Zeke for a short walk in the morning. It was too cold for Lucy, even with her coat. I was glad we went down Wildlife Trail, because I found evidence that at least one fox is still in the neighborhood. I had not seen one since the county spent a week resurfacing Wildlife Trail. At first I thought the tracks were from one of the cats, but they were too big and too widely spaced. The tracks came from the woods across the street, where the foxes seemed to have a den. They came into our driveway, but veered off away from the house and then back into the street.

It looks like this one spends some of its time in a culvert. Its tracks led to one end of the culvert and disappeared. There were tracks at the other end, too.

Zeke’s tracks made a neat little intertwined pattern with the fox’s.snow tracks

Zeke seemed completely uninterested in the tracks in the snow, so I assume there was little or no scent. He was interested in the area around the end of the culvert. I assume this means the scent was stronger, although I don’t know whether that means the fox spends time in the culvert.

We walked into the woods at the bottom of Wildlife Trail. A rabbit had been hopping around down there.

Later I found what was probably a crow’s tracks behind the house. I wasn’t sure at first, but when I followed the tracks, they led to a double circle and then disappeared. It was a neat trick if it wasn’t a bird.

Added Thursday night:

It was 16 degrees up at our house on Thursday morning. I drove down the mountain a little after 8 am, and the thermometer in my truck showed 1F. I haven’t seen a temperature that low in a long time. The cab got warm, but the engine didn’t get to normal operating temperature until I reached the long uphill grade that I couldn’t get down on Tuesday night. That was about 30 miles from home. Motor oils and other lubricants must have really improved in the last 30 years. I drove a 1984 Nissan pickup during the winter of 1984-85 when the temperature in Atlanta dropped to about 5F. It never got warm enough to give heat in the cab, and when I took my foot off the gas, the truck slowed down like I had thrown out an anchor.

 

White Snow, or The Long Drive Home

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It wasn’t supposed to snow in Rome. The TV weather forecasters said the area below Atlanta would get snow on Tuesday, not us. So I drove to Huntsville Monday expecting it to be cold, but nothing else. By about the middle of the morning on Tuesday there was a little snow blowing around the parking lot where I work. There was so little I wasn’t sure whether it was snow or salt scattered by the building maintenance people. By then, though, it was snowing more at home, and Leah wanted me to leave early. So I left work at 1:30 Central Time for what would normally be a drive of a little over two hours. Six hours and an extra 130 miles later I pulled into our driveway.

The first two thirds of the drive was without incident. There was a little packed snow between the lanes on the climb from the Tennessee River outside Scottosboro (made infamous by the trial of the Scottsboro Boys) up onto Sand Mountain, but nothing serious. The rolling terrain on top of the mountain had a little snow, but the highway was mainly clear. The highway descending into Fort Payne (The Sock Capital of the World, and also home of the country music group Alabama) was almost clear, but there was a line of traffic trying to get up the grade going back towards Huntsville. The roads in Fort Payne were covered with a thin layer of packed snow. The temperature varied from around 15 to 19 F, so there was not much melting.

Downtown Fort Payne

Downtown Fort Payne

The grade up Lookout Mountain on the other side of Fort Payne was covered with dirty, packed snow with a sprinkling of gravel, apparently from the highway department. The road over Lookout Mountain was also covered with a thin layer of packed snow, but it didn’t give the truck any problems. I thought I would be home fairly soon, despite driving slowly.

This should have been a clue.

Why are those trucks parked there?

Why are those trucks parked there?

The trucks were parked in a lot in front of a little gas station and general store a couple of miles from the grade down the mountain. When I was about a quarter mile from the start of the grade, there was a tanker truck sideways across both lanes and a line of cars on the other side waiting to go down the hill. I was about a half an hour from home, but I had no choice but to turn around and try another way. It was about 10 miles back to Fort Payne and the interstate.

To make a long story short, I ended up driving up Interstate 59 to Interstate 24 to Chattanooga, and then down Interstate 75 to the Rome exit. I drove a significant portion of  those extra 130 miles at between 30 and 50, depending on how much snow was in the road and how much traffic there was.

I hadn’t driven our newish truck (2010 three-quarter ton Dodge with four wheel drive) in slippery conditions, but I was quite pleased with it. At one traffic light a rear-wheel-drive car spun its tires through the entire green light, while I pulled around and drove away without any problems. Leah was worried that I would have to park the truck at the bottom of the mountain and walk up. About four vehicles had made the one and a half mile drive up Lavender Mountain in the snow. The truck made it five.

It turns out that Lavender Trail is a regular highway for wildlife.

Dimly-lit, snow-covered road, with footprints

Dimly-lit, snow-covered road, with footprints

I think the tracks I saw were fox and deer. All three of the pictures here were made with my iPhone. The last one was pushing it, because I was relying entirely on the truck’s headlights.

There was about two inches of snow on the ground around our house, but one deck railing that was protected somewhat from the wind had four or five inches. I think that’s about what we got, but the wind blew it around and prevented much accumulation.

This is the second time I have had to do this. About four years ago the same thing happened, only with more snow.

Apparently traffic in Atlanta was pretty much a nightmare. Roads were impassable and emergency shelters were opened for stranded drivers. There are school and business closings for Wednesday all over the state. It’s amazing what an inch or two of packed snow can do to traffic here in the South.

Winter came knocking

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It was 23 F when we got up Monday morning. It’s already been colder this winter, but this is the first time the Atlanta TV weather forecasters have been so excited (“The polar vortex is coming! Run! Run!”). The temperature slowly dropped all day.

Leah was worried about the cats Sunday night, so we let Zoe, Smokey and Sylvester stay inside in addition to Chloe, who has been staying in since it got cold. But nature calls, so we put them out for a while in the morning.

Smokey did not like it.

Let me in

Let me in

With the wind, it felt much colder than 23, so I thought Monday morning when I walked the dogs around the house it would be a good time to wear my LL Bean fur cap. My brother gave it to me a long time ago when he lived near Pittsburgh, but I haven’t had a good excuse to wear it until now. Plus I lost it for a while.

I was not as unhappy as I look here

I was not as unhappy as I look here

If you look closely you can see the red star from the Russian pin I got at the 1996 Atlanta Olympics. I think it fits the cap.

Russian star

Russian star

The dogs wore their winter coats when I took them out Monday morning. I didn’t take either of them for their usual long walk, but I did take Zeke for a shorter one. I left Lucy inside; small dogs lose heat faster than big dogs. We had a little snow overnight, and there were still a few flakes floating around when we walked. They were small and glittering, and they seemed to float more than fall. When a little breeze stirred them, they all took off in the same direction like a flock of birds.

Monday night was even colder. It was 6 F when we got up this morning (Tuesday). The dogs got two short walks around the house for purposes of nature calls, but only Zeke will get a longer walk, and he’ll have to wait till this afternoon when the temperature is supposed to reach 26. The cats, of course, stayed in Monday night, too. Unfortunately, Rusty and Dusty won’t come in, so they had to rough it in the cathouse or somewhere in the garage. I hope Dusty didn’t spend the night in a culvert.

The very low (for us) temperatures are an opportunity to see heat transfer at work. As you all know, wind chill is a great favorite of weather forecasters. One of the Atlanta guys said that it only refers to effects on humans, and that is partially correct. If the temperature is 35 with a wind chill of 20, a human will feel very cold without a coat, but a glass of water still won’t freeze. On the other hand, if it’s 6 F with a wind chill of -20 F, a house will lose heat much more quickly than it would in still air. We saw that last night. We (and by “we” I mean “I”) kept a fire going in our wood-burning stove all night, getting up twice to feed it. The stove kept the basement at around 77, but our bedroom dropped to 68 and the bathroom dropped to 66. Ice formed on the sliding glass doors with aluminum frames. And even with the stove going, our heat pump came on several times Monday night. Under more normal conditions, the stove alone will keep the house warm enough that the heating system doesn’t come on. Six degrees and wind removes too much heat from the house for the stove to keep up with it. At these temperatures a heat pump relies almost entirely on resistance heating, which is going to show up in our power bill.

The house complained about the temperature. The deck on the back and the front walk popped and banged all night as the wood shrank and rearranged itself.

This morning dawned clear. The sun is struggling to warm our bedroom and the living room, but I expect by afternoon the combination of the sun and the stove will have warmed the house enough that Leah can take off her anorak and mukluks.

These temperatures are not especially low for many places in the US, but they are for Georgia. Significant winter weather events are rare in Georgia. I remember them by their stories.

The first winter storm I remember was an ice storm in 1959 or 1960, when I was in elementary school. Rain fell onto cold surfaces and froze into a solid, glass-like coat. All night long we listened to the pine branches snapping off. They sounded like gunshots. The limbs fell onto power lines that were already sagging from their own ice coating, and the lines broke. We lost power for a long time. Our house was heated with a floor furnace, and, of course, the thermostat didn’t work without electricity. But my father went under the house and managed to get the furnace to run steadily without electrical power. I think we were the only ones on our street with heat.

The next I remember was a cold snap a few years later that happened after a lot of rain had caused the streams and rivers to flood. Ice formed on the on the flooded creek where my father took my brother and me and our dog Mike for a walk. Mike went out on the ice and fell through. We heard him barking. We went down to the edge of the ice and called and called. He struggled, putting his front feet on the ice and trying to haul himself out, but every time he got up, the ice broke under him. He finally pulled himself out. I don’t know what would have happened if he had not been able to get out. My father would not have gone after him and left us there, and he certainly never would have let us go after him. I know what I would do today if it happened with Zeke or even Lucy.

The next one was the winter of 1984-1985, when I was in graduate school at Georgia Tech. I lived in a small apartment at the back of a house two blocks from Northside Drive and about two miles from school. When I drove back to my apartment after school, the snow was coming down in hard little balls, but the streets were clear. As I always did, I took my dog Jesse to a field across Northside, where I let her run for a half hour or so. By the time I had changed my clothes and walked the two blocks to Northside, cars were sliding sideways down the hill. The storm hit so quickly that some of the faculty in the Atmospheric Sciences Department were caught by surprise and had to spend the night at school.

Later that evening I was watching TV when my roommate, an undergrad, came in with a young female student. The girl stayed a few minutes and then said she was going to her apartment. I thought she had driven my roommate home, but I finally put two and two together and asked him if they had walked from campus. When he said they had, I said we couldn’t let her try to walk home. She was planning to walk about 10 miles out beyond the perimeter road through the snow in a dress and open shoes. That’s when I came up with my first rule of life: Never wear shoes you can’t walk home in.

We got into my little Honda station wagon and started out. By that time the roads were nearly impassible, and what was passable was usually blocked by cars driven by idiots. We spent about two hours finding a way out to the girl’s apartment, going first one way, and then another. The snow was already so deep that at one traffic jam I turned around in a parking lot and drove over the curb without realizing it.

When we let the girl out at her apartment, I think she said thanks.

This weather is severe, but I don’t think I’ll have a story for it. It’s just cold, and the stove is warm.

stove

Fog, glorious fog

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On overcast or rainy days around here, it’s fairly common for the bottoms of the clouds to be lower than the top of Lavender Mountain. Those low clouds become thick fog for us up here on the mountain. Sometimes the fog closes in and visibility drops to a few dozen yards. We have had that kind of weather several times over the last few days.

We have flood lights on the corners of the house and some bright low-voltage spot lights at ground level behind the house. When I walk the dogs around the house late on a foggy night, I cast a shadow on the fog itself. It’s hard to get a decent photograph of it. This is the best I could do.

My shadow in the fog

My shadow in the fog

I had to enhance this image in Photoshop Elements. That caused a lot of noise in the image that makes the fog seem grainy. But one thing you can see is the brightness of the fog around my shadow.

This is what you get when you use a flash. The reflected light completely washes out anything in the scene, and the resulting image is nothing but noise.

Nothing but fog

Nothing but fog

Zeke sat down to wait for me while I fiddled with the camera. I tried to get a shot of him, but, even though he was close and there did not seem to be much fog between us, this is all I could get.

Zeke in the fog, waiting patiently

Zeke in the fog, waiting patiently

I took shot of the front of the house. It was a kind of neat scene, but it was also a hard image to get, especially with the little point-and-shoot camera I was using.

The front of the house

The front of the house

All of these images illustrate some of the interesting things that happen when light goes through fog. The effects are caused by the scattering of light from water drops. Water drops tend to scatter light strongly back towards the source. That’s what happened when I used the flash; a lot of light was scattered (reflected) right back at the camera, flooding the sensor and washing out anything that otherwise have been visible in the scene.

Light is also scattered strongly into the forward direction, that is, the direction that the light was originally traveling. When you see a bright light in a foggy scene, like the floodlights in the picture of the front of our house, you will probably notice that the light itself looks bright, but there is also a lot of glare around the light. That is light being forward scattered.

The way light is scattered into all directions around a water drop is called the scattering phase function. If you could see it plotted, you would see that some light is scattered into all directions around a water drop, but there is a lot more in the backward (towards the light source) and forward directions.

All this is fairly wonky, but it leads to some really neat things, like, for example, the glory. The glory has been noted for hundreds, if not thousands of years, mainly in regions with high mountains where the clouds are sometimes lower than the tops of the mountains. If a person is on the top of a mountain, and there are clouds below the top of the mountain, and the sun is behind his back, sometimes if he looks down towards the clouds, he will see his shadow cast on the clouds, and there will be something that looks like a halo around his head. That is the glory.

If two people are standing together looking down at their shadows, each one will see a glory only around his own body. It’s easy to understand why someone who doesn’t know what causes a glory to think that it must mean that the person who sees it is special.

Probably the most common place to see glories today is from an airliner. If the sun is in the right place, and the plane is flying over clouds, and you are in the right seat to see the plane’s shadow, you will probably see a glory around the shadow of the plane.

There are several explanations for the glory, but they seem unnecessarily complicated to me. It seems to me that the scattering phase function explains it pretty well. When the light is coming from directly behind you, your head will cast a shadow, but the light that passes around your head will be scattered strongly back towards the source; in other words, directly back towards you. Thus you will see a bright area around the shadow of your head. The glory is often colored, which also doesn’t seem to require a very complicated explanation, since a similar effect can be seen in every rainbow.

You can see a more pedestrian version of this almost any time the sun is out. Just stand so that you can see your own shadow. Most of the time whatever surface you are standing on will tend to reflect light more strongly directly back towards the source than in other directions. This will cause the ground or other surface to look brighter right around the shadow of your head. This is often a subtle effect, but if you look carefully you ought to be able to see it. A roughish surface, like grass, is better than a smooth surface like a concrete patio.

So, when you’re out looking around, keep looking up, but don’t forget to look down sometimes, too.

Sunrise in pastels

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Some sunrises are dramatic and some are not. This morning’s was not dramatic, but it was nice.

Tuesday morning's sunrise

Tuesday morning’s sunrise

The fog was not as thick down in the valley as in the previous post, but there was some there. It was 68 up on the mountain when we got up. When I drove down into the lowlands, it was 64, a nice inversion. Inversions with fairly high humidity are self limiting, because radiation fog tends to form when the air cools enough. The temperature can’t drop much more once the fog forms.