Climate Change: Part 4 – How Storms & Hurricanes Form

This miniseries is a layman’s explanation of the causes of Climate Change and its effects upon Global Warming.

The formation of storms and hurricanes are largely a mystery to most people. This post will attempt to explain how they are formed in light of the recent rash of hurricanes that have threatened and damaged this nation resulting in hundreds of billions of dollars in damages and loss of life to take some of the mystery out of it and how Climate Change may have played a role.

The formation of Clouds

Storms are the accumulation of energy in the air and the instability caused when there is a difference in energy distribution in the atmosphere.  This instability is most often caused by a difference in temperature distribution but it can also be differences in air mass or density. Energy is potentially stored in the atmosphere by light particles or moisture since this is far more massive than air and able to store much higher concentrations of energy. Enormous amounts of energy can be stored in highly moistened air, but as long as this energy is distributed fairly homogeneously nothing happens except perhaps fog. So very moist humidity areas will not necessarily result in the formation of storms. But when there are large temperature gradients, representing high energy and air mass imbalances in the atmosphere, it can cause often rapid air movement. Then this stored energy together with more source of moisture, such as an ocean, can start to take on a life of its own and amplify this movement in a positive feedback loop as it picks up more moisture from the large body of water and further moving this massive moist air mass up into the atmosphere. Moisture starts condensing into tiny droplets as it moves above a certain altitude where temperatures are below the dew point forming clouds.

Other Storms Not Based upon Moisture

Dry air can also pick up heated sand practical from the ground which adds energy to the surrounding air-dust mass create huge sandstorm from tiny particles of hot sand containing large amounts of energy. This energy then gets passed on to the surrounding air molecules resulting in huge prolonged sandstorms such as in the Gobi Desert in northern China that drop sand all over that region annually and turn the sky yellow a thousand miles away. Snowstorms are similar to sandstorms where lightweight snowflakes are picked up by winds from the ground heating or cooling the air around causing instability and turbulence snowstorms and whiteouts. But sand and snow storms are confined to only a few areas because there are so few places with large expands of sand or snow whereas two-thirds of the earth’s surface is covered with water. So storms like hurricanes due to moisture are by far the most prevalent source of stormy weather conditions experienced by people on a large scale.

Formation of Storms

So how do large storms and hurricanes develop? Energy creates stormes. Large bodies of water are needed to create huge storms. Large bodies of warm water are needed to form huge and powerful storms. Keep in mind that everywhere there is cold air above a certain altitude. But there isn’t always a source of warm water. Most warm waters can be found near the equator where the sun’s energy passes through the least amount of atmosphere to the water below warming it near the surface where evaporation occurs. So it is near the equator that most major storms first start forming. As evaporation occurs convection winds blow it to higher and cooler altitudes until it is below the dew point temperature in which the air can no longer hold so much moisture and it condenses out into tiny droplets forming clouds. As more moisture is added to these clouds the clouds grow larger and higher and the droplets eventually freeze at the higher altitudes forming cumulous clouds. These storms can dump enormous amounts of rain and create large storms.

Formation of Hurricane

The earth rotates on its axis results in the equator moves faster than the poles. So the air above also moves faster at the equator than at the poles. The earth rotates from the east to the west. If a storm is large and dense enough with storm clouds, say more than 75 miles across, the earth’s rotation can cause the outer parts of the storm to start rotating in a clockwise direction in the northern hemisphere since the part of the storm closest to the equator moves the fasted and the part closest to the north pole moves the slowest. Thus a tropical depression is formed. As more and more tropical ocean moisture gets added to such large formations they gather in energy and velocity winding up in the typical hurricane spiral formation. The pressure at the center of the storm becomes lower than the rest of the storm as the spiral compresses more energy towards the center. This causes the center of the storm to have the highest concentration of energy and thus highest wind speeds. A Category 1 hurricane is defined when one of these tropical depressions has maximum sustained winds of 75 mph. A Category 5 hurricane has maximum sustained winds of 155 mph and will cause catastrophic damage. As hurricanes hit landfall the lack of moisture and the friction of land cause the wind speeds to decrees causing them to die unless they head back out to sea. I’m not sure why there is an eye at the center of a hurricane where there is a lull and clear skies.

It should be noted that hurricanes and typhoons (they are actually the same thing but in different parts of the word) happen only on the eastern sides of continents. Moistened air is blown towards continents (leading edge) due to the rotation of the earth from east to west. The western sides of large continents (trailing edge) are dryer where winds blow away from the land to the ocean so have less moisture forming clouds. That, in a nutshell, is how storms and hurricanes are formed.

Climate Change

Climate Change causes the oceans to warm up producing more warmer waters and larger amounts of evaporative energy. This results in the formation of more frequent and larger storms and hurricanes as we have been seeing as one after another tropical depression turns into a major hurricane at the equator before heading up the southeastern part of continents.

Links to this Miniseries:-

  1. Climate Change: Part 1 – The Fundamentals
  2. Climate Change: Part 2  – Greenhouse Gases
  3. Climate Change: Part 3 – Runaway Climate Change
  4. Climate Change: Part 4 – How Storms & Hurricanes Form
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3 Responses to Climate Change: Part 4 – How Storms & Hurricanes Form

  1. Pingback: Climate Change: Part 3 – Runaway Climate Change | ouR Social Conscience

  2. Pingback: Climate Change: Part 2 – Greenhouse Gas Emissions | ouR Social Conscience

  3. Pingback: Climate Change: Part 1 – The Fundamentals | ouR Social Conscience

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