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11 Booming Facts About Thunderstorms

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Thunderstorms can inspire the entire range of human emotion with their vivid displays of nature's fury. Storms are used to set an ominous tone in spooky stories, even as they bring much-needed relief to parched fields or distressed humans on a hot day. These torrents are as fascinating to study as they are to watch, and as common as they are, they're actually quite complex.

1. WHAT GOES UP …

Warm, moist air is the fuel that feeds a thunderstorm the energy it needs to survive. A column of warm air quickly rising through the atmosphere is known as an updraft, and these upward winds can pack a punch. The strength of an updraft depends on how great the temperature difference is between different levels of the atmosphere. An updraft can exceed 100 mph in the strongest thunderstorms.

2. THE TOP OF THE STORM GETS SMOOSHED.

An updraft will continue skyward until the rising air is no longer warmer than the air around it. The rising air spreads out at this point, creating flat, anvil-like clouds that make a distant thunderstorm such a spectacular sight. Even more stunning are mammatus clouds, bubble-shaped formations that can develop along the bottom of anvils. Due to the strength of the storm needed to produce these vivid formations, they're often associated with severe thunderstorms.

3. RAIN DRAGS A STORM DOWN.

Once the weight of the raindrops suspended in a budding thunderstorm grows too heavy for the updraft to hold, or once raindrops fall out of the sides of the updraft, they begin falling to the ground as precipitation. The falling rain drags cooler air toward the ground, creating a downdraft, or that cool breeze you feel before and during a storm. Most downdrafts are pretty weak, but some are strong enough to cause damaging winds at the surface. A thunderstorm dies once the cool air of the downdraft cuts off the flow of warm air to the updraft, starving the storm and causing it to rain itself out.

4. THERE ARE DIFFERENT TYPES OF THUNDERSTORMS.

Not all thunderstorms are the same. There are three main types of thunderstorms. Most thunderstorms are single-cell, or a storm that pulses up, rains for half an hour, and dissipates. When that storm collapses, the wind from its downdraft can trigger more storms in a chain reaction. There are also multi-cell thunderstorms, the most common of which are squall lines. The third type of storm is a supercell, or a thunderstorm that has a rotating updraft. The twisting updraft helps supercells survive for many hours and produce more severe weather—larger hail, higher winds, and stronger tornadoes—than a normal thunderstorm.

5. HAIL BOUNCES AROUND LIKE POPCORN.

If temperatures are just right in the middle of a thunderstorm, some of the raindrops will begin to freeze as they bounce around in the updraft. The up-down motion of the newly formed hailstone will cause more liquid to accumulate on the outside of the stone, a process that causes hailstones to grow in layers like an onion. The vast majority of hail isn't large enough to cause any damage, but the updrafts in some thunderstorms are so intense that they can support hailstones the size of softballs or larger.

6. THUNDERSTORMS ARE ELECTRIFYING.

The friction between ice crystals, raindrops, and hailstones moving around in a storm can cause an electrostatic buildup between the clouds and the ground that releases its energy in a brilliant flash of lightning. Lightning is hotter than the surface of the Sun, heating the air up so fast that the shockwave radiates out in a sonic boom we hear as thunder. All thunder is caused by lightning, and all lightning causes thunder. There's no such thing as "heat lightning," a term used to describe lightning seen in the distance not accompanied by thunder. This phenomenon is simply lightning that occurs too far away for you to hear the thunder.

7. STORMS ARE PRETTY HEAVY.

Water is heavy. We look at clouds floating effortlessly through the sky and don't think about the sheer amount of weight hanging above our heads. One cumulus cloud can weigh more than 1 million pounds. When it comes to a billowing thunderstorm, though, the weight can go up tremendously depending on how much rain it's holding. We're lucky the rain doesn't all fall at once.

8. THEY BLOCK OUT THE SUN.

All of that water looming above us also has the effect of blotting out the sun. The sky gets dark before a thunderstorm because the sunshine can't make it through the vast column of water in an especially wet thunderstorm. The much-feared green sky before a storm, often thought to presage a tornado, is usually caused by sunlight refracting through both heavy rain and hailstones.

9. HUMANS CAN ACCIDENTALLY CAUSE THEM.

Humans can't control the weather, but our actions can indirectly influence where thunderstorms form. Studies have shown that increased temperatures in and around cities, due to the urban heat island effect, can trigger thunderstorms that wouldn't have otherwise formed in these areas if the city and its streets weren't there. There's also some evidence that unstable air warmed by steam released by the cooling stacks of nuclear power plants can trigger small storms.

10. IT CAN THUNDER WHEN IT'S SNOWING.

Thunder doesn't only happen when it's raining. Intense bands of snow can develop during blizzards and lake effect snow events in much the same way that a regular thunderstorm would form when it's warm out. These strong bands can produce lightning and loud cracks of thunder all while dumping copious amounts of snow in a short period of time.

11. YES, IT CAN RAIN FROGS.

There's some truth to the myth that it can rain frogs, fish, and other odd objects. If a strong tornado lofts debris high into a storm, that debris has to fall down somewhere. If a tornado sucks the water out of a pond, for example, it's very possible that the critters that used to be in the water will fall on populated areas. Hail can also form embedded with small pieces of debris like tree branches as the debris serves as a nucleus around which the water can freeze.

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Weather Watch
3 Ways We Can (Kind of) Control the Weather, and 5 Ways We Can't

Humans have the incredible ability to control the world around us. We can move mountains and land robots on other planets. We can keep each other alive longer than ever before and even bring entire species back from the brink of extinction. But despite all of our leaps forward, we're still unable to control the weather, a tremendous force that affects every human being on this planet. Still, humans have come up with some pretty crafty ways of influencing the weather—in small doses.

1. WE CAN MAKE IT RAIN … SOMEWHAT.

The desire to control weather has been a mainstay of imagination since, well, the beginning of imagination. The fortunes of entire societies can hinge on flood or drought. We have strong motivation to want to create a rainstorm in one spot or moderate snowfall in another. But the greatest success we've ever had is a technique that can (maybe) encourage a tiny bit of rain to form over a tiny area.

Cloud seeding is a process through which fine particles like silver iodide are released into a cloud in order to encourage the formation of rain or snow. These particulates serve as a nucleus around which water vapor can condense and turn into a raindrop or a snowflake. This is most commonly done with small airplanes, but it can also be accomplished by launching tiny rockets or flares from the ground.

In theory, the practice of cloud seeding could have innumerable uses around the world, including crop maintenance, providing drinking water, and even possibly weakening severe thunderstorms or hurricanes. There's only one problem: It doesn't work all that well.

The effectiveness of cloud seeding is a hot topic of debate among scientists, but most studies have either found negligible impacts on precipitation, or the researchers were unable to determine the exact impact of cloud seeding. Cloud seeding is a great concept if you want to help one cloud produce a little extra rain or snow just to say you can do it, but it's not the way to go if you're desperate and want to trigger a deluge. This process requires the pre-existing presence of clouds, so even if the technology improves in the future, it's not a viable solution for drought-stricken areas that haven't seen meaningful clouds in weeks.

2. WE CAN DEFINITELY ATTRACT LIGHTNING USING ROCKETS.

Lightning safety is one of the things you learn from a very young age. "When thunder roars, go indoors," as the motto goes. We learn to stay away from open areas and water during thunderstorms. But what if you wanted to attract lightning? It's surprisingly easy to do if you have the right equipment and really, really want to encounter some of nature's fury.

Scientists who want to study lightning can bring it right to their doorstep by using specially designed rockets attached to conductive wires that lead to the ground below. When a thunderstorm blows over the observation station, operators can launch these rockets up into the clouds to trigger a lightning strike that follows the wire right down to the ground where the rocket was launched. Voila, instant lightning. Just add rocket fuel.

3. WE CAN CREATE CLOUDS AND HEAT—EVEN WHEN WE DON'T MEAN TO.

Most of the ways in which we control—or, more accurately, influence—the weather is through indirect human actions—often unintentional. "Whoops, the nuclear power plant just caused a snowstorm" isn't as crazy as it sounds. Steam stacks can and do produce clouds and updrafts with enough intensity to create rain or snow immediately downwind. The very presence of cities can generate microclimates with warmer temperatures and heavier rain. And there's also climate change, the process in which our accumulated actions over a long period of time are influencing the very climate itself.

BUT WE CAN'T DO THE FIVE FOLLOWING THINGS.

Despite our limited ability to influence a few aspects of weather over small areas, there are some rather colorful conspiracy theories about whether or not governments and organizations are telling the whole truth about how much we can accomplish with today's technology. There are folks who insist that the trails of condensed water vapor, or "contrails," left behind jet aircraft are really chemicals being sprayed for sinister purposes. (They're not.) There are theories that a high-frequency, high-power array of antennas deep in the Alaskan wilderness can control every weather disaster in the world. (It doesn't.) There are even folks who insist that Doppler weather radar carries enough energy to "zap" storms into existence on demand. (Dr. Evil wishes.)

There are also some bizarre and unworkable theories that are offered in good faith. A meteorologist a few years ago opined on whether building an excessively tall wall across middle America could disrupt weather patterns that could lead to tornado activity. And every year the National Hurricane Center is peppered with questions about whether or not detonating nuclear bombs in a hurricane would disrupt the storm's structure. Unfortunately, while pseudoscience offers up great theories to test in the movies, when it comes to weather, we're still not in control.

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Weather Watch
NASA Figures Out Why When It Rains, It (Sometimes) Drizzles
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What’s the difference between drizzle and rain? It has to do with updrafts, according to new research by NASA scientists into the previously unexplained phenomenon of why drizzle occurs where it does.

The answer, published in the Quarterly Journal of the Royal Meteorological Society, could help improve how weather and climate models treat rainfall, making predictions more accurate.

Previously, climate researchers thought that drizzle could be explained by the presence of aerosols in the atmosphere. The microscopic particles are present in greater quantities over land than over the ocean, and by that logic, there should be more drizzle over land than over the ocean. But that's not the case, as Hanii Takahashi and her colleagues at the Jet Propulsion Laboratory found. Instead, whether or not rain becomes full droplets or stays as a fine drizzle depends on updrafts—a warm current of air that rises from the ground.

Stronger updrafts keep drizzle droplets (which are four times smaller than a raindrop) floating inside a cloud longer, allowing them to grow into full-sized rain drops that fall to the ground in the splatters we all know and love. In weaker updrafts, though, the precipitation falls before the drops form, as that light drizzle. That explains why it drizzles more over the ocean than over land—because updrafts are weaker over the ocean. A low-lying cloud over the ocean is more likely to produce drizzle than a low-lying cloud over land, which will probably produce rain.

This could have an impact on climate modeling as well as short-term weather forecasts. Current models make it difficult to model future surface temperatures of the Earth while still maintaining accurate projections about the amount of precipitation. Right now, most models that project realistic surface temperatures predict an unrealistic amount of drizzle in the future, according to a NASA statement. This finding could bring those predictions back down to a more realistic level.

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