What's the Difference Between Sleet, Hail, Graupel, and Wintry Mix?

No matter what background or tradition or religion or belief system you identify with, I think we can all agree: when crazy stuff starts falling from the sky, things get weird. Turns out there are so many crazy things falling from the sky these days that we now must expand our vocabulary. My friends, it’s time to get cozy with hailsleetgraupel (yes—this is a real thing), and wintry mix.

But first: some background. Hail, sleet, graupel, and wintry mix are all forms of precipitation that start off as snowSnow stays snow when the temperature between the clouds and the ground stays at around 32°F the entire way down; it’s when the temperature gets warmer somewhere en route that interesting stuff starts to happen.

Sleet is what forms when there are warmer temperatures in the air and near- or below-freezing temperatures on the ground, or when cold air “sandwiches” a pocket of warmer air. This combination causes snowflakes to melt on their way down and then re-freeze as they get closer to the ground, turning into translucent little pellets of ice.  

Graupel, on the other hand, happens when there are freezing temperatures in the air and above-freezing temperatures closer to the ground. Snowflakes get caked in near-frozen drops of rain, forming soft, opaque white balls akin to what the National Weather Service so aptly describes as “Dippin’ Dots.” For such an ugly name, I personally think graupel sounds quite lovely; it’s like snow on steroids, or like the pearl-sugar topping on a brioche, but soft.

Wintry mix, as one might guess, is a gross mix of snow, graupel, sleet, and freezing rain, because turns out multiple things can fall out of the sky at the same time! However, instead of the clouds spewing out a trail mix–like mixture, which would actually be kind of cool, we get any of those forms of precipitation falling in areas very close to each other, or switching off as the day progresses. (Meteorologists use the term “wintry mix” to essentially avoid getting too specific.) According to this story in the New Yorker, wintry mix most often happens in the central or eastern United States, thanks to a lovely concoction of cold air from Canada, warm air from the Gulf of Mexico, stormy air from the Rocky Mountains, and western air coming in on a jet stream. These all create a setting perfect for crazy frozen things to form and fall to Earth.

Lastly, we have hail, which only falls during thunderstorms and is actually most common in warmer conditions during the spring, summer, and fall. Hail starts as soft, snow-like particles that form in the below-freezing air at the top of thunderstorms (because it’s still cold up there, even in the summertime). As these particles fall into the storm, ice crystals and cloud droplets freeze onto them, and they stay suspended in the clouds for a while, gathering up more frozen stuff. When the pellets get too heavy, or when the winds that push them up into the clouds get too weak to keep them afloat, they start falling to the ground. 

Hail is usually only the size of a penny, but the largest recorded hailstone fell in 1986 over the Gopalganj district of Pakistan and was… 2.25 pounds. Imagine the terror when that fell out of the sky. Stay safe out there!

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What's the Difference Between Spruce, Fir, and Pine Trees?

Merry Christmas! Chances are, if you’re celebrating the holiday, you have a tree hanging out indoors somewhere, festooned in lights and popcorn and ornaments and whatever else you feel like draping on its scented limbs. But what’s the difference between that specimen in your living room and the giant one in Rockefeller Center, or the ones you can see from your frosted window, whose needles whisper softly in the winter wind? Let’s get to know our holiday evergreens. 

Spruce, fir, and pine trees are part of the class pinopsida, and they’re all conifers: their leaves take the form of thin, narrow needles, and they shed cones in order to reproduce. (Cones are essentially fancy seeds.) 

Firs, at least in America, are the classic Christmas trees; tall and narrow in appearance, their branches grow in thickly and luxuriously, oftentimes obscuring the trunk from view. The needles attach individually to each branch, and are secured by a doodad that looks almost like a tiny suction cup. Those needles are sharply pointed and somewhat flexible; however, since they’re flat, you can’t really roll them between your fingers. Firs have a smooth bark, and their cones are somewhat enigmatic; they grow towards the tops of the trees, and they usually break apart before falling to the ground. If you do get your hands on one, it will be green, elliptical in shape, and probably oozing with sap.

Like firs, spruce trees have needles that are attached individually to each branch, though without that suction-cup situation. Their needles are stiffer than firs and have four sides to them, making them easily roll-able between your fingers. The scales of spruce cones will be narrow and feel flexible, and their bark is the roughest and scaliest of the notable evergreens.

Pine trees have a more-sparse branch distribution than their fir and spruce cousins, making them the least likely Christmas tree contender. And unlike firs and spruces, they have two, tree, or five needles coming out of the same spot on each branch, with needles that are softer and more pliant. Pine-tree bark is jagged and flaky, and while their cones start out green and flexible, they grow brown and woody as they mature.

In case you need some more tree trivia to whip out at the dinner table tonight, how’s this: What’s the deal with Christmas trees, anyway? People have actually been putting evergreen trees in their homes since long before the birth of Jesus Christ; they were thought to ward off witches, ghosts, and evil spirits. The trees held particular significance around the time of the winter solstice, when people celebrated the return of the sun; the evergreen-ness of the evergreens was reminiscent of life and growth. In the sixteenth century, it’s believed that Martin Luther himself was the first person to put candles on an indoor tree; on the way home from a sermon, he was struck by how the stars looked twinkling above the evergreens, and he wanted to bring that brilliance into his home. It took a while, however, for Americans to get into the spirit; in 1659, in fact, the court of Massachusetts actually made it illegal to do anything besides attend church on Christmas, and people were fined for having decorations. But after an influx of German and Irish immigrants in the late nineteenth century, Americans finally started to get into the whole decorated-tree tradition, and the modern Christmas era officially began. 

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What's the Difference Between a Pond and a Lake?

Psh, you might be thinking. This is a lame one. I totally know the difference between a pond and a lake. I just swam in one this weekend, for God’s sake! I dove into its cool waters after manning the grill all day! I drank a bottle of ice-cold rose while lounging lazily on a swan-shaped float positioned on its very surface! This is a dumb newsletter!

Sorry to burst your bubble, folks, but to cut to the chase: THERE IS NO DIFFERENCE.

Let’s get into it. Scientists in the field of liminology (the study of inland waters) have been trying to categorize the differences between lakes, ponds, and wetlands for quite some time. (In evolutionary terms, a “lentic” body of water—meaning an inland body of water with currents that do not flow in a continuous and definite direction—should go from a lake to a pond to a wetland.) Some scientists tried to use thermal stratification, saying a lake was deep enough to have two to three layers of different temperatures during warmer-weather months. Other scientists tried to use plant growth, saying that ponds were shallow enough for sunlight to reach the bottom, so that rooted plants could grow across their entire width. 

However, none of this matters. Us common folk are completely incapable of rational thought and/or respecting the fruits of scientific inquiry and started calling things PONDS and LAKES completely arbitrarily. (Scientists ended up concluding that they couldn’t divide these things into precise categories, either.) So when it comes to the actual naming of things—with actual bodies of water called Sebago Lake or Walden Pond or whatever place you swam in this weekend—there is not even an attempt at any sort of scientific decency. For example, Echo “Lake” in Conway, NH has a surface area of 14 acres and is 11 feet deep, while Island “Pond” in Derry, NH has a surface area of almost 500 acres and is 80 feet deep. In fact, it’s common for a body of water to switch from a lake to a pond (or vice versa) to better appeal to potential real-estate buyers—would you rather live near Dishwater Pond or Mirror Lake?

If you’re itching for a little distinction to get you through the week, take comfort in knowing that scientists do recognize the difference between “deep” ponds and lakes and “shallow” ponds and lakes“Deep” ponds and lakes have some areas of underwater plant growth, along with deeper portions where sunlight does not hit the bottom; they also have distinct thermal layers in the summer. “Shallow” ponds and lakes have rooted plant growth across the entire bottom, consist of only one thermal layer, and usually have more muddy sediments than their deeper brethren.

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What's the Difference Between Weather and Climate?

When one discusses both the climate and the weather, one is drawing from the same bucket of building blocks: think temperature, humidity, solar radiation, precipitation, wind speed, etc. However, there are important—and far-reaching—distinctions between the two concepts, all that hinge around duration. As Encyclopedia Britannica so aptly puts it: “Weather and climate relate to one another in much the same way that an inning in a baseball game compares with the whole game.”

Let’s start with weather. When I say that it’s wet and chilly in New York City this morning, I’m describing the weather: it’s a set of conditions in the atmosphere for a short period of time, such as the day, night, or at some point in either. Weather can change from hour to hour or even minute to minute, and can refer to places as specific as neighboring towns, or parts of a city, or even opposite sides of a street. 

Climate, on the other hand, can be thought of as the average weather conditions over a long period of time—usually thirty years or longer. While weather is constantly changing, climate is (or should be) less volatile. In addition, climate usually refers to a large swath of geography, such as large parts of a country, or whole countries, or even parts of the planet. (The atmospheric conditions of the Sahara desert or the Amazon basin or the Arctic Circle, for example, would generally be referred to as climate, not weather.) 

Examining these two definitions, it’s worth nothing how dangerous it is to think of weather and climate as the same thing. It’s normal for weather to be constantly changing; it’s not normal for climate to be doing so. When climates shift even slightly, the consequences can be much more severe than a freak afternoon thunderstorm. (If you haven’t seen this deeply terrifying New York magazine piece, it’s worth a read.) We’ll dig into the differences between climate change and global warming another week—stay tuned. For now, stay dry!

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What's the Difference Between Tornadoes, Hurricanes, and Typhoons?

As one might know from the Wizard of Oz or seventh-grade science class, tornadoes form over land, most commonly over the Central Plains in the spring or early summer, when moist, warm air from the Gulf of Mexico meets the cold, dry continental air coming from the Northwest. Compared to hurricanes and typhoons, they’re rather small and short-lived: the largest tornadoes are about one to one-and-a-half miles in diameter, and they rarely will travel more than six miles. The average life span of a tornado is approximately ten minutes. 

Both hurricanes and typhoons are the same type of storm; they’re the highest level of what scientists call a “tropical cyclone,” which is defined by the National Ocean Service as “a rotating, organized system of clouds and thunderstorms that originates over tropical or subtropical waters and has closed, low-level circulation.” The difference between the two lies only in where the storm originates; anything over the northwest Pacific is a typhoon, and anything over the North Atlantic, central North Pacific, and eastern North Pacific is a hurricane. (For storms over the South Pacific and Indian Ocean, the general term “tropical cyclone” is used.) Tropical depressions and tropical storms are less-intense versions of their brethren; a storm’s winds must be at least 74 miles per hour in order to be placed in the hurricane/typhoon category. And unlike smaller-scale tornadoes, hurricane and typhoons can be 60 to 1000 miles in diameter; can last for several days; and can travel thousands of miles. 

Some more fun facts:

  • Hurricanes always rotate counterclockwise in the Northern hemisphere and clockwise in the Southern hemisphere. Tornadoes usually spin in the same manner, though there can be rare “anticlyconic” tornadoes that spin in the opposite direction.
  • Hurricanes, typhoons, and tornadoes all have eyes: an area of mostly calm weather in the center of the storm. The most violent conditions are in the “eyewall,” the area directly surrounding the eye.
  • A tornado that forms over water is called a “waterspout.” 

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What's the Difference Between Soil and Dirt?

For today’s answer, we’re turning to Patrick Megonigal, an ecosystem ecologist at the Smithsonian Environmental Research Center. According to Megonigal, as told to Science Newssoil is:

the compilation of minerals, air, water, animals and other living matter (and their wastes or decaying bodies) that accumulate in layers and become compacted over time. 

These layers—or “horizons”—are defined as the topsoil, subsoil, and parent soil.
 
And dirt? Megonigal defines dirt as “displaced soil.”
 
Huh? How could that be? I checked in with Frank R. Spellman’s book Contaminated Sediments in Freshwater Systems, and he agrees:

Dirt is misplaced soil—soil where we don’t want it, contaminating our hands or clothes, tracked in on the floor.

So there you have it, folks. Everything is subjective. Nothing is real. Dirt is just displaced soil. Happy Tuesday!

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