4 Reliable Ways to Get Severe Weather Warnings—and 1 Unreliable One

Brian Davidson/Getty Images
Brian Davidson/Getty Images

Tornado season ramps up this month. Seconds count when your life is on the line. Your ability to quickly react to a dangerous situation is critical. Knowing how and when to act is especially important when severe weather bears down on your home or office. Warnings from meteorologists are the best way you can keep yourself safe from dangerous weather. If you wait until you can hear the wind or see the water rising, it’s probably too late to get to safety. Having a decent amount of lead time to get you and your family to a safe place can save your life, and it’s possible if you know how to get the alerts as fast as possible.

1. YOUR CELL PHONE CAN SAVE YOUR LIFE.

Most modern smartphones are equipped with a nifty feature known as Wireless Emergency Alerts (WEA). If you own one, you’ve likely been startled by the abrupt, screeching tone that suddenly emanates from your device.

These alerts are targeted to you based on the nearest cell phone tower to your location. This enables you to receive alerts only for hazards that are expected to affect you and not some town 30 miles away. The WEA can be activated for tornadoes, severe thunderstorms, flash floods, and other local emergencies like dust storms, hazmat situations, and even AMBER Alerts.

However, these alerts only help if you don’t shut them off. Lots of people wind up disabling their phone’s emergency alerts after the first unwanted interruption. That’s not a good idea. The alerts are proven life-savers. Just recently, eight people in southern Georgia sought shelter after their cell phones alerted them to an approaching tornado. The storm destroyed the home, yet everyone inside survived.

Wireless Emergency Alerts are enabled by default on iOS and Android devices. You can check your settings on an iOS device by opening your Settings app and looking under the “notifications” option. If you have an Android device, look for the “emergency alerts” option in the settings of your phone’s default text messaging app.

2. SPRING FOR A WEATHER RADIO.

It’s always good to have a reliable backup in case severe weather alerts don’t come through on your cell phone. Investing in a NOAA Weather Radio is a smart way to keep you and your family safe when bad weather strikes. Modern weather radios allow you to program your county’s unique six-digit code into the device so it can sound a loud alarm when a watch or warning is issued for your county. Some higher-end devices even allow you to select which alerts you’d like to receive and which you’d rather ignore.

NOAA Weather Radios aren’t foolproof—during the April 27, 2011, tornado outbreak, early morning storms knocked out multiple weather radio transmitters before an astonishing 363 tornadoes tore through later that afternoon—but it’s an excellent backup to ensure that you receive an alert if your television goes out or your cell phone doesn’t work.

3. WATCH THE TV NEWS.

Getting your news from the television may seem outdated in the age of the internet, but your local television news stations are a great resource for detailed weather information. Most local stations go wall-to-wall with coverage when there are severe thunderstorms or tornadoes in their coverage area, and a trained meteorologist will track the storm with Doppler radar, showing the worst of the storm as it moves from neighborhood to neighborhood. Television is prone to outages and interruptions, but it’s always helpful to listen to a calm voice guiding you through a bad storm.

4. IF ALL ELSE FAILS, FM RADIO STILL EXISTS!

If you’re in your car, you can usually switch on the radio and search for a station broadcasting live weather information. When a particularly dangerous tornado outbreak is in progress, many radio stations—especially in tornado alley—will preempt programming and switch over to a live audio feed from a local television station’s coverage of the storms.

5. TORNADO SIRENS ARE AN UNRELIABLE RELIC OF THE PAST.

One of the first ways entire communities were alerted to an approaching tornado was the use of tornado sirens. These loud outdoor alerting systems were designed to tell people who were outdoors to seek shelter inside before the storm arrived. Despite widespread belief in their effectiveness and continued use in rural areas, tornado sirens are an unreliable way to receive warnings. The sirens are not designed to be heard indoors, and variables likes wind direction, power outages, and equipment failures can render them useless. Don’t rely on tornado sirens for your warnings. Stick with modern technology to keep you safe.

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.

SECTIONS

arrow
LIVE SMARTER