We all know that as we go higher, it gets colder. Then it stands to reason, any two places with the same altitude will be as cold as each other.
But that isn’t the case! Ooty and Shimla, two famous hill stations in India, are at similar altitudes but experience very different temperatures.
Why?
Why would any two places at the same altitude have different temperatures?
In this video, we find out.
Correction: At 2:55, I say that Ooty is 14.1°N of the equator. It is actually 11.4°N of the equator, and the figure in the video is correct.
Transcript of the video
Place your palm horizontally 10 cm over a candle flame.
In 5 seconds or so, your palm will start burning up and you’ll want to move your hand away (please do!)
Now, place your palm over the candle flame at the same height, but tilt it slightly. The center of your palm will feel less hot, and you will probably be able to keep your hand over the flame a little longer.
Tilt it slightly more, and you will barely feel the heat on your palm and you can hold it there as long as you want.
If only I remembered this little experiment in my first climate science class.
In that class, the professor asked us a question.
“Why does it snow in Shimla and not in Ooty, even though they have the same elevation?”
That’s easy!
.
.
.
.
Damn it!
If you are unaware of Indian geography, Shimla and Ooty are both famous hill stations in India. Shimla is a city in North India, at an elevation of 2276 meters above mean sea level. Ooty is in South India, rising to 2240 meters above mean sea level. Despite very similar attitudes, it is much colder in Shimla than in Ooty.
Looking at this from a broader perspective, we are always taught that as we go higher, it gets colder.
Then why would any two locations with the same altitude experience different temperatures?
After enjoying our discomfort for a bit—you know, the way teachers generally do—he finally gave us the answer.
Ooty and Shimla are at different latitudes.
Ah! Latitude.
How?
The earth is a curved surface. Because of this curvature, different latitudes receive the Sun’s heat at different angles.
At the equator, the sunlight falls perpendicular to the surface of the earth. Just like in our candle experiment, this high angle means more energy is focused on the surface, making the region much hotter.
As we move to higher latitudes, sunlight falls at lower and lower angles. Again, from our candle experiment, we know that with smaller angles between the surface and the heat source, it feels less hot.
Sunlight also has to travel a longer distance through the atmosphere at higher latitudes, and the atmosphere is really good at dispersing the sunlight and reducing the intensity of the light. This helps in the cooling.
So, let’s look at my professor’s question again. Ooty lies on latitude 11.4°N (I misspoke in the video) and is 1271 km away from the equator. It is within the tropical zone. It receives direct sunlight at a high angle, making it hot.
Well, it doesn’t snow there!
Shimla, on the other hand, lies on latitude 31°N and is more than twice as far from the equator as Ooty: 3460 km. This reduces the angle between the sun’s rays and the surface, making Shimla colder than Ooty.
And that is why it snows in Shimla and not in Ooty.
Now I just need a time machine……
I hope you enjoyed the video and you found it interesting and useful! Have misleadingly simple questions left you stumped? Leave them in the comments!
Thank you for watching Eco-intelligent, as we try to make the world, ecologically intelligent.
Eco-intelligent™ 
This blog made me happy. So so happy and nostalgic.
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Really glad!
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Ooty does reach 0 ° C. My family went from Blore, to Ooty in Dec 2012 and while getting into the car on the last morning, at 0700, I saw the Swift windshield was looking opaque. There was a 0.25 inch ice layer! I used some water from a Sprite bottle to melt and remove it. My hands were chilled and I had to blow on them for a few minutes before I could drive. The hotel watchman, when asked, confirmed that some clear nights in Nov- Jan there could be ice formation on surfaces like windshield!
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Hi, thanks for sharing the story!
Yes, it can reaching freezing temperatures in Ooty, and usually that happens in La Nina years. I checked and 2012 was a La Nina year!
From what I understood, during La Nina, the air gets much colder because of the influence of jet streams. This allows temperatures in Ooty to drop sufficiently to counter the effect of the Sun, making it snow. There is also more moisture in the air during La Nina years.
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Hi, your logic is correct but that is not the exact reason why it snows in Shimla not in ooty.
Precipation is dependent on winds and relief. It is not directly related to latitude or altitude. Western Himalayas where Shimla is located experiences snow bearing western disturbances that blow from europe and central asia in winters. Also, Shimla is surrounded by much higher ranges that provide relief and check the snow bearing winds. Ooty on the other hand does not experience any snow bearing winds also, the ranges of eastern/western ghats are too low to check snow bearing winds if any.
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You are right, the wind and relief conditions do play a role in the climatic conditions of Shimla and Ooty. But the critical factor remains the latitudinal difference. For example, if both Shimla and Ooty are hit with the western disturbance winds, it would snow in Shimla but it would rain in Ooty.
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Once snow crystals form in the atmosphere, they grow by absorbing surrounding water droplets. The snowflakes we end up seeing on the ground are an accumulation of these ice crystals. This magnified image of snow crystals was captured by a low-temperature scanning electron microscope (SEM). The pseudo colors commonly found in SEM images are computer generated, and in this case highlight the different flake formations.
—Credit: Agricultural Research Service, United States Department of Agriculture
Whether winter storms produce snow relies heavily on temperature, but not necessarily the temperature we feel here on the ground. Snow forms when the atmospheric temperature is at or below freezing (0 degrees Celsius or 32 degrees Fahrenheit) and there is a minimum amount of moisture in the air. If the ground temperature is at or below freezing, the snow will reach the ground. However, the snow can still reach the ground when the ground temperature is above freezing if the conditions are just right. In this case, snowflakes will begin to melt as they reach this higher temperature layer; the melting creates evaporative cooling which cools the air immediately around the snowflake. This cooling retards melting. As a general rule, though, snow will not form if the ground temperature is at least 5 degrees Celsius (41 degrees Fahrenheit).
While it can be too warm to snow, it cannot be too cold to snow. Snow can occur even at incredibly low temperatures as long as there is some source of moisture and some way to lift or cool the air. It is true, however, that most heavy snowfalls occur when there is relatively warm air near the ground—typically -9 degrees Celsius (15 degrees Fahrenheit) or warmer—since warmer air can hold more water vapor.
Because snow formation requires moisture, very cold but very dry areas may rarely receive snow. Antarctica’s Dry Valleys, for instance, form the largest ice-free portion of the continent. The Dry Valleys are quite cold but have very low humidity, and strong winds help wick any remaining moisture from the air. As a result, this extremely cold region receives little snow.
Snow on the ground
The character of the snow surface after a snowfall depends on the original form of the crystals and on the weather conditions present when the snow fell. For example, when a snowfall is accompanied by strong winds, the snow crystals are broken into smaller fragments that can become more densely packed. After a snowfall, snow may melt or evaporate, or it may persist for long periods. If snow persists on the ground, the texture, size, and shape of individual grains will change even while the snow temperature remains below freezing, or they may melt and refreeze over time, and will eventually become compressed by subsequent snowfalls.
Over the winter season, the snowpack typically accumulates and develops a complex layered structure made up of a variety of snow grains, reflecting the weather and climate conditions prevailing at the time of deposition as well as changes within the snow cover over time.
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Thanks a lot Sajaul! I was seeking this information for long. Wonderfully explained
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