TEVA TALK : The Wonder of Weather

The great American writer, Mark Twain, once remarked that, in New England, the weather changes so frequently that you can study all the different types of weather by simply standing outside for the day and waiting for the weather to march by. Twain must have written this before visiting Baltimore because people here need only stand in front of their houses for a few hours to experience the full gamut of weather conditions.

Over the past few months, our lives have been turned upside-down in so many ways that we are desperate for a return to routine. Yet there is so much we still don’t know: what our children’s education will look like in September, when the economy will recover, and when we can go to shul and weddings again. Ironically, it is the unpredictability of Baltimore’s weather that is the one thing people can count on with certainty these days.

So, with the kids at home and climatic conditions right outside our windows, it’s an ideal time to learn about the fascinating phenomenon we call “the weather.”

Heat

Everyone agrees that Baltimore summers are hot. There is some disagreement, however, as to exactly how hot it got on July 10, 1935, the hottest day in Baltimore’s history. Most claim it was a sweltering 107 degrees, while a few insist it reached an excruciating 109! Honestly, at that point, the officials should stop standing around with their thermometers and get back inside with a tall glass of iced tea. Too hot is too hot, and two degrees won’t change that.

So this summer, when it is only 92 degrees and you are rapidly running out of iced tea, you can always “shelter in place” with the air conditioning, an option not available in 1935, while reminding yourself, “Well, at least it’s not 109!” Keep in mind, too, that 92 outside your front door could actually be a lot more a few blocks away. Areas with few trees do not benefit from the cooling effects that nature brings. Asphalt absorbs heat and holds city blocks hostage in its suffocating grip.

Last summer, a heatscape study took temperature readings throughout Baltimore and discovered that downtown Baltimore, with its parking lots, bare brick buildings, and miles of pavement, measured 16 degrees hotter than surrounding forested neighborhoods. Sixteen degrees is the difference between a “warm” afternoon in the backyard at 87, as compared with melting on your way home from work at 103! This research led to suggestions to plant more trees in urban areas, including empty lots, in order to alleviate the oppressive heat. We can’t change the weather, but we can do our part to make it more comfortable.

Humidity

In addition to the heat, Baltimore summers follow two weather patterns: rainy and sweaty. Either way, you are going to get wet. The real villain in Baltimore is humidity. Humidity (on a simplified level) refers to how much moisture is locked in the air, and in Baltimore the answer to that question is all of it. Research has revealed that between 40 and 50 percent humidity is ideal for comfort and health. Baltimore, however, averages over 60 percent relative humidity, which means that for over half our year we are guaranteed to be “uncomfortable,” with many days reaching over 90 percent!

Everyone is familiar with the water cycle. We know that when water is heated by the sun, it evaporates, changing from a liquid to a gas called “water vapor,” and floats into the air. The higher it floats, the cooler the air becomes, until the water vapor is cooled enough to become liquid again and condenses into clouds. When the clouds become “heavy” and “full” of water, the liquid water falls back down toward the earth as rain. The cycle then repeats.

The temperature at which water changes from a gas to a liquid is called the “dew point.” One hundred percent relative humidity is when the air temperature is the same as the dew point. The air is as full of water vapor as possible. You cannot see the water, but you can feel it sticking to every part of your body. Our bodies expel heat by sweating, and the evaporating sweat cools us down. But if the air is already full of water, the sweat can’t evaporate and has nowhere to go except down our foreheads. The result: we feel hotter than the actual temperature would indicate. The opposite is also true: If the relative humidity is low, you will feel cooler than the real temperature. You will have to take my word on that one, though; I don’t foresee us experiencing that phenomenon in Baltimore anytime soon.

Thunderstorms

With its high temperatures and consistently high humidity, Baltimore summers, which last from May through September, are the ideal breeding ground for thunderstorms. Many thunderstorms form when the sun warms moist air such that it rapidly rises through the atmosphere. At higher altitudes, the air cools quickly, forming ice crystals. These rub against one another as they move around in the air and generate electrical charges. The positive charges form at the top of the cloud and the negative charges gather at the bottom. A positive charge is then built up on the ground under the cloud and reaches up through high points like trees and tall buildings to meet the opposite negative charge right above it. The charges continue to build up and eventually connect, resulting in a lightning strike.

Lightning goes with thunder, of course. While thunder is not dangerous in itself, if you can hear thunder, you are in danger of lightning. If you are swimming when a storm rolls in, even in a backyard kiddie pool, the most important thing is to get out and away from the water the minute you hear thunder, and not to reenter the water until 30 minutes after its last rumble has faded away. Lightning regularly strikes water since water is an excellent conductor of electricity, and you are in very real danger. If you are driving, it is best to pull over if visibility is low and stay inside your car. The metal frame of your car – not the rubber in your tires as many erroneously believe – will protect you from lightning, but only if the windows are closed and you are not touching the metal parts that are inside your car, including the steering wheel. Also, this is only true if your car has a metal top. Even with the roof closed, you are not safe sitting in a convertible during a lightning storm. Given the unpredictability of lightning, it is wise to just stay inside until the storm passes, which usually last only 20 to 30 minutes. Thunderstorms sometimes form in chains, so that once one passes, others quickly follow. Just because the skies are finally quiet, doesn’t mean the rest of the day will be clear. For our own safety, we have to be constantly vigilant of additional approaching storms.

Snowfall

A high percentage of Baltimoreans ostensibly suffer from chionophobia: the fear of snow. The mere threat of possible snowfall is enough to send many residents scrambling to do emergency food shopping in case the roads become impassable (a source of amusement to those from Boston or Chicago!). Most of the time, though, snowmen remain unbuilt, and sleds remain unused by the shed.

I am still uncertain as to exactly where the line lies between the number of years one needs to live in Baltimore to realize that it does indeed snow here and the number of years one needs to live in Baltimore to adamantly deny that it ever does. It is a bit astounding to us non-native Baltimoreans to see how many people are sincerely surprised every time it does snow. I will share a secret with you: it does snow in Baltimore. Really. The city did not spend its time and money posting snow evacuation route signs and setting up salt boxes in strategic locations for nothing. While we are spared from living with months of mounds of snow and constant biting wind like some of our northern neighbors, a light sprinkling of snow now and then is common, just enough to make kids dream about snowmen and send their parents in panic to buy emergency canned goods at the grocery stores.

Most of you reading this article have personally witnessed the greatest snowfall in Baltimore’s history, which occurred from January 22 to 23, 2016. Over the course of those two days, which was Shabbos, 29.2 inches of snow fell on the homes and cars of shocked Baltimore residents (because it doesn’t snow in Baltimore, right?) and the children could finally go sledding.

Understanding how snow forms reveals the fact that it is really a tremendous chesed. The winter air holds water vapor, just like the summer air, but the water vapor is frozen in the form of tiny ice crystals, which don’t melt on the way down as they do in the summer. If those sharp ice-crystals came down as piercing projectiles and as fast as raindrops fall, they would tear apart plants and damage houses, and it would be painful to venture outside.

Snow is heavy, too. We know this from personal experience because every few years, when it actually snows enough to require shoveling (instead of waiting a few hours for the sun to melt it off of your driveway), your back is sore the next morning. And it is only once you finish piling the snow on one side of your driveway that you realize, too late, that you just blocked all your garbage cans – garbage pick-up is tomorrow morning – and you have to move the snow pile you just made. Then you really feel the weight of the snow. Yet when it falls from the sky, a snowflake lands on your eyelash with the lightest touch, and you can simply blink it away. What a chesed.

We are all so fortunate to live in Baltimore, a community characterized by a focus on personal growth and acceptance of one another. But what can we do about the weather? Well, nothing, really, aside from to buy extra clothes, carry an umbrella at all times, dress in layers, and try to remember to bring home the jacket that you needed in the morning. In the winter, don’t be afraid of the snow (it doesn’t snow in Baltimore anyway), and in the summer, drink a lot of water, stay hydrated, stay in the air conditioning when the temperature and humidity soar, and stay safe.

Debbie Glazer lives in Pikesville with her husband and seven children and teaches Language Arts in Bnos Yisroel High School. She can often be found either writing or reading and loves to share her passion for the written word with others.

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A Weather Activity

How much difference does shade make? Let’s do an experiment and see.

Trees are incredibly important for many reasons. In addition to providing us with oxygen to breathe and homes for dozens of animals and birds, trees provide us with cooling shade. You know from your walks around the neighborhood that you are instinctively drawn to walk down the side of the street lined with trees as opposed to the side that is bare.

To test what a big difference shade can make, take two ice cubes that are similar in size. Please one in the shade and another in the sun. Choose a location where you can see both ice cubes at the same time. Now wait, but not too long. You will be surprised at how much faster the ice cube in the sun melts!

A Weather Craft

You and your family can personally witness the entire water cycle from the comfort of your own home! All you need is a zip-lock bag, a permanent marker, some strong tape, and some water. I recommend using a gallon-size zip-lock bag, but this demonstration will work with any size.

Hold the bag with the opening facing up. Approximately two-thirds of the way down, draw a wavy line with your permanent marker across the entire bag to show where the ocean is. Between the top of the bag (where the opening is) and the ocean, draw some clouds. At this point you are ready to witness the water cycle, but feel free to add any other details you want, such as birds, trees, boats, distant mountains, gazebos (wait, that is a bit too much). 

Now, simply fill the zip-lock bag with water up until the wavy water that you drew.  Seal the bag very well and hang it with tape on a sunny window, zipper side up. (We want a water-cycle demonstration, not a mabul demonstration.) It is important that you choose a window that gets direct sunlight. 

You will see results by the next day (as long as it isn’t cloudy). The water within your water-cycle display will constantly move through its phases: from evaporation to condensation to precipitation – all without you getting wet (unless your tape was not strong enough). 

Note: For an added effect, you can add two or three drops of blue food coloring to the water before you seal the bag.