5 Record-Breaking Weather Facts of 2016

After a brief period of heavy rain in drought-choked California, wildflowers bloomed near Caliente on March 4, 2016. Image Credit: David McNew/Getty Images

 
Thank goodness 2016 is almost over. It’s hard to come across one person who enjoyed much of what the year threw at us—and that’s true of its weather, too. Whether you were baked by extreme heat or drenched by never-ending rains, 2016 was an active, record-breaking year that left few parts of the U.S. untouched by tumult. Here’s a quick look back at how the weather treated us in 2016.

1. 2016 WAS LIKELY THE WARMEST YEAR EVER RECORDED.

The weather is more than what you see in your backyard. We only ever personally experience a small fraction of the weather events that unfold every day around the world, but we’re all impacted by large-scale trends like the record-setting warmth of 2016.

2016 will very likely go down as the warmest year ever recorded, the third such year in a row, topping 2015 as the previous holder of this dubious distinction. NOAA’s year-to-date temperature data for the world through the end of November has 2016 coming in 0.94°C warmer than normal, which almost guarantees that 2016 will come in slightly warmer than 2015’s astounding year-end anomaly of 0.89°C.

Some of this year’s record warmth is attributable to El Niño, the anomalous warming of the ocean water near the equator in the eastern Pacific Ocean, but that doesn’t explain all of it. This year continued an undeniable trend that shows that our atmosphere is warming at a fairly steady pace; in fact, including this year, six of the ten warmest years recorded since 1880 have occurred since 2010. If the warming trend continues in the years ahead, it will likely result in adverse situations like more intense and prolonged droughts in some areas, more frequent flooding due to rising sea levels and heavier rainfall in others, and longer, deadlier heat waves.

2. WE HAVEN’T SEEN MANY RECORD LOWS AS A RESULT.

Arctic air descending over the United States on December 17, 2016. Image Credit: Dennis Mersereau

 
The recent cold snap that froze much of the U.S. in the middle of December felt exceptionally cold—with low temperatures dipping well below zero across many states—but it’s easy to forget that it used to get much colder than that on a pretty regular basis. As a result, this bone-chilling cold didn’t set as many record lows as one would think. That’s not an uncommon situation these days.

Climate Central recently took a look at the ratio of daily record lows to daily record highs and found that the latter significantly outnumbers the former. For every record low we’ve seen in the United States in 2016, there have been at least six record highs. Climate Central notes that the number of record highs and lows should equal out over time in a “stable climate,” but we’re in anything but a stable climate these days. 

3. THE U.S. SUFFERED FROM HISTORIC FLOODS.

On the precipitation side of things, extreme flooding events were by far the largest cause of weather disasters this year in the United States, and there were two particularly devastating flooding events in 2016. The first unfolded across Louisiana in August, the result of a storm system that stalled out over the eastern part of the state and dumped up to 30 inches of rain over a short period of time. The extreme rain led to flooding that caused more than $8.7 billion in damages, killed more than a dozen people, and forced tens of thousands of people out of their homes.

The other flooding disaster was caused by Hurricane Matthew, a powerful storm that grazed the Florida and Georgia coasts before coming ashore in the Carolinas at the beginning of October. The hurricane merged with a frontal system over North Carolina and focused one to two feet of intense rainfall on the eastern part of the state. Much as we saw in Louisiana, the floods claimed thousands of homes and resulted in multiple fatalities.

4. WHERE IT DIDN’T RAIN, IT REALLY DIDN’T RAIN.

The U.S. Drought Monitor as of December 13, 2016. Image credit: USDM

 
The split between feast and famine was stark this year. While the West Coast’s drought slowly got a bit better, much of the eastern parts of the United States slipped into a disruptive, and at times, destructive drought. The drought is particularly bad in interior parts of the southeast, where states like Georgia and Alabama have slipped into their worst drought in a decade. The dry earth has led to devastating wildfires that have claimed thousands of homes and killed numerous people. The extreme dryness will likely last through a significant portion of 2017, and affected areas may not see any noticeable relief until next summer’s hurricane season.

5. TORNADO ACTIVITY AND TORNADO DEATHS ARE NEAR RECORD LOWS.

Still, not all of the wacky weather we’ve seen in 2016 was bad. The Storm Prediction Center’s data through the end of December shows that 2016 is very close to the fewest number of tornadoes recorded in one year since 1950. The United States typically sees around a thousand confirmed tornadoes every year, but that activity has been relatively minimal for the past couple of years. Adjusted for inflation—removing false reports and duplicate reports for the same tornado—2016 has seen 897 reported tornadoes through December 19, 2016. That’s significantly lower than the previous low-point of 944.

Tornadoes can grow into violent monsters that destroy entire towns, but these beastly formations are surprisingly fragile. Tornado formation requires precise amounts of wind shear, instability, and moisture—too much or too little of one ingredient will prevent a storm from producing tornadoes. This natural limitation is why only a tiny fraction of thunderstorms ever spawn tornadoes.

The near-record lack of tornadoes so far this year has had the added benefit of resulting in one of the lowest tornado death tolls on record. On average, about 98 people die every year as a direct result of injuries sustained in tornadoes [PDF]. Only 17 people have died as a result of tornadoes so far in 2016, the second-lowest number on record since 1940. Only 1986 saw a lower tornado death toll, when just 15 people were killed.

Why Does Humidity Make Us Feel Hotter?

Tomwang112/iStock via Getty Images
Tomwang112/iStock via Getty Images

With temperatures spiking around the country, we thought it might be a good time to answer some questions about the heat index—and why humidity makes us feel hotter.

Why does humidity make us feel hotter?

To answer that question, we need to talk about getting sweaty.

As you probably remember from your high school biology class, one of the ways our bodies cool themselves is by sweating. The sweat then evaporates from our skin, and it carries heat away from the body as it leaves.

Humidity throws a wrench in that system of evaporative cooling, though. As relative humidity increases, the evaporation of sweat from our skin slows down. Instead, the sweat just drips off of us, which leaves us with all of the stinkiness and none of the cooling effect. Thus, when the humidity spikes, our bodies effectively lose a key tool that could normally be used to cool us down.

What's relative about relative humidity?

We all know that humidity refers to the amount of water contained in the air. However, as the air’s temperature changes, so does the amount of water the air can hold. (Air can hold more water vapor as the temperature heats up.) Relative humidity compares the actual humidity to the maximum amount of water vapor the air can hold at any given temperature.

Whose idea was the heat index?

While the notion of humidity making days feel warmer is painfully apparent to anyone who has ever been outside on a soupy day, our current system owes a big debt to Robert G. Steadman, an academic textile researcher. In a 1979 research paper called, “An Assessment of Sultriness, Parts I and II,” Steadman laid out the basic factors that would affect how hot a person felt under a given set of conditions, and meteorologists soon used his work to derive a simplified formula for calculating heat index.

The formula is long and cumbersome, but luckily it can be transformed into easy-to-read charts. Today your local meteorologist just needs to know the air temperature and the relative humidity, and the chart will tell him or her the rest.

Is the heat index calculation the same for everyone?

Not quite, but it’s close. Steadman’s original research was founded on the idea of a “typical” person who was outdoors under a very precise set of conditions. Specifically, Steadman’s everyman was 5’7” tall, weighed 147 pounds, wore long pants and a short-sleeved shirt, and was walking at just over three miles per hour into a slight breeze in the shade. Any deviations from these conditions will affect how the heat/humidity combo feels to a certain person.

What difference does being in the shade make?

Quite a big one. All of the National Weather Service’s charts for calculating the heat index make the reasonable assumption that folks will look for shade when it’s oppressively hot and muggy out. Direct sunlight can add up to 15 degrees to the calculated heat index.

How does wind affect how dangerous the heat is?

Normally, when we think of wind on a hot day, we think of a nice, cooling breeze. That’s the normal state of affairs, but when the weather is really, really hot—think high-90s hot—a dry wind actually heats us up. When it’s that hot out, wind actually draws sweat away from our bodies before it can evaporate to help cool us down. Thanks to this effect, what might have been a cool breeze acts more like a convection oven.

When should I start worrying about high heat index readings?

The National Weather Service has a handy four-tiered system to tell you how dire the heat situation is. At the most severe level, when the heat index is over 130, that's classified as "Extreme Danger" and the risk of heat stroke is highly likely with continued exposure. Things get less scary as you move down the ladder, but even on "Danger" days, when the heat index ranges from 105 to 130, you probably don’t want to be outside. According to the service, that’s when prolonged exposure and/or physical activity make sunstroke, heat cramps, and heat exhaustion likely, while heat stroke is possible.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

This article has been updated for 2019.

Is the Heat Index Real?

MarianVejcik/iStock via Getty Images
MarianVejcik/iStock via Getty Images

Complaining about the humidity is a mainstay of small talk. “It’s not the heat that gets you, it’s the humidity” is a common refrain around the South, just as “it’s a dry heat” is a go-to line in the desert Southwest. The clichés aren’t wrong on this one—a hot and humid day can have a dramatic effect on both your comfort and your health. We can measure this very real impact on your body using the heat index. 

The heat index is the temperature it feels like to your body when you factor in both the actual air temperature and the amount of moisture in the air. If the heat index is 103°F, that means that the combination of heat and humidity has a similar physical impact on your body as it would if the actual air temperature were 103°F. Even though it’s tempting to think of the heat index as an exaggerated temperature that only exists to make the heat sound worse than it really is, scientists came up with the measurements after decades of medical and meteorological research devoted to studying the impact of heat and humidity on the human body. It’s the real deal.

The dew point is an important component of the heat index. The dew point is the temperature at which the air would reach 100 percent relative humidity, or become fully saturated with moisture like on a foggy morning. Since cooler air can’t hold as much moisture as warmer air, lower dew points reflect lower moisture levels and higher dew points indicate higher moisture levels. Dew points below 60°F are comfortable, while readings reaching 70°F and even 80°F range from muggy to downright oppressive.

Measuring humidity on a hot day is important because moisture is how your body naturally cools itself off. Your sweat cools the surface of your skin through a process known as evaporative cooling. If the air is packed with moisture, it takes longer for your sweat to evaporate than it would in more normal conditions, preventing you from cooling off efficiently. The inability to lower your body temperature when it’s hot can quickly lead to medical emergencies like heat exhaustion or heat stroke, which is why the heat index is such an important measurement to pay attention to during the summer months.

The heat index is generally considered “dangerous” once the value climbs above 105°F, and your risk of falling ill increases the higher the heat index climbs.

Dry climates can have the opposite effect on your body, with the distinct lack of moisture in the air making it feel cooler to your body than it really is. Summers get oppressively hot in places like Arizona and Iraq, but the heat doesn’t affect residents as severely because the air is extremely dry. Dew points in desert regions can hover at or below 32°F even when the air temperature is well above 100°F, which is about as dry as it can get in the natural world.  

In 2016, a city in Kuwait measured the all-time highest confirmed temperature ever recorded in the eastern hemisphere, where temperatures climbed to a sweltering 129°F during the day on July 21, 2016. The dew point there at the same time was nearly 100 degrees cooler, leading to a heat index of just 110°F, much lower than the actual air temperature. That’s not necessarily a good thing. Extreme heat combined with extreme aridity can make your sweat evaporate too efficiently, quickly dehydrating you and potentially leading to medical emergencies similar to those you would experience in a much more humid region of the world. 

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

This story has been updated for 2019.

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