Month Archives

May 2017

Heat Index: Deadlier Than Lightning

When we think of weather-related dangers during the summer months, our minds tend to wander towards the catastrophic. Things like tornadoes, floods, fires, or hurricanes. Even lightning is frightening. But are these huge events really the things we should be worried about, day in and day out? On average, heat index kills and hospitalizes more people than all of these other things combined.


Heat Index

Heat index is a basic calculation using temperature and relative humidity and is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature. The National Weather Service (NWS) and National Oceanic and Atmospheric Administration (NOAA) has put together this easy to use chart to explain the relationship.


NOAA heat index chart

As you can see, the dangers of heat stroke and heat exhaustion can start to set in at temperatures as low as 80 degrees Fahrenheit. As humidity rises, you quickly get into the Extreme Caution and Danger zones.

Physical activity also contributes to your body’s ability to withstand high heat indexes. The more humid the air around you becomes, the more difficult it is for your sweat to evaporate and cool your body properly.


Heat Index – the silent killer

heat index sun

As noted in the article that accompanies the chart above, the heat index numbers were calculated assuming shady and light wind conditions. However, when we’re out hiking, working, and enjoying the outdoors, chances are we’re in direct sunlight and there may or may not be any wind. This can intensify heat index up to 15 degrees Fahrenheit. Your round of golf on the back nine just got a little riskier under the “right” conditions.

Additionally, it goes on to say that “strong winds, particularly with very hot, dry air, can be extremely hazardous.” This might sound contrary to what was just said about heat index, but having spent time in Death Valley, CA, I can tell you it’s true.

We all know that “dry heat” doesn’t feel as hot as “humid heat.” We also know that a light breeze can make us feel cooler too. So not only does the dry heat make us feel cool, but the breeze makes us feel cool, too; and both occurring at the same time makes us feel extra cool. It makes it easy to forget that we’re outside straining our bodies in 105 degree weather in direct sunlight. A quick look at the chart and we see that it only needs to be about 47% humidity and we’re in extreme danger. (Not to mention how much these conditions dehydrate our bodies, exacerbating the onset of heat exhaustion.)


Heat Index is everyone’s problem

It has become (or ‘still is,’ depending on how you view it) such a major issue this year that Drew Brees from the New Orleans Saints is taking part in a public awareness campaign and speaking about his experiences with it.



Tragically, there seems to be at least one high-profile death every year from athletes being exposed and not carefully monitored while practicing and playing in these conditions.

In 2001, Korey Stringer, a professional football player for the Minnesota Vikings, collapsed during training camp and never recovered. In 2011, a Dutch music promoter and his girlfriend died hiking in Joshua Tree National Park. In 2014, Dave Legeno, perhaps best known for his role in ‘Harry Potter,’ collapsed while hiking in Death Valley. In this 2009 article on Live Science, they cite an annual report from the University of North Carolina that states, “Since 1995, 33 football players have died from heat stroke.”


Don’t let heat index win

Now that you know what heat index is and just how dangerous it can be, here are a few tips to make sure you stay safe this summer:

Check the weather and use common sense

If it’s going to be 90 degrees and 75% humidity, you’re already in the danger zone. If you were planning to go on a 40 mile bike ride, see if you can postpone it a day or go in the evening when it’s cooler.

Seek shade, rest often

If you have to be out in Danger or Extreme Danger conditions, find as much shade as possible as frequently as possible. Don’t let your body heat up to the point you can’t cool it down naturally.

Drink a lot of water

By ingesting cool water, we can slightly decrease our core temperature momentarily. On top of that, making sure that we’re well hydrated ensures we have enough fluids to produce sweat (our bodies’ natural cooling mechanism).

Watch for signs of heat exhaustion

WebMD lists these common symptoms of heat exhaustion:

Throbbing headache
Dizziness and light-headedness
Lack of sweating despite the heat
Red, hot, and dry skin
Muscle weakness or cramps
Nausea and vomiting
Rapid heartbeat, which may be either strong or weak
Rapid, shallow breathing
Behavioral changes such as confusion, disorientation, or staggering


Carry an INO Weather Pro™

INO Weather Pro


We’re a bit biased, but we think this could solve a lot of problems for solo athletes, coaches, trainers, crew chiefs, and just about anyone that loves to be active or works outdoors. Not only does it provide temperature and humidity as separate measurements, but it does the heat index calculation for you and provides that as well.


Have fun and stay safe out there!


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Bizarre Lightning Phenomena

An interesting article from ListVerse lists 10 ‘bizarre’ lightning phenomena as impressive as the lightning itself. To read the full list, click here.

·       Restoring sight to the blind – a truck driver was blinded in a traffic accident. Nine years later his sight was miraculously restored when he was struck by lightning after taking shelter under a tree. Later that evening his vision began to clear, eventually restoring his ability to read.

Lightning Cures Cancer

·       Curing Cancer – in 1932 a man suffering from a diagnosis of terminal cancer and near the end of his life way laying in a hammock outside which was threaded with metal wires. Lightning struck the trees around his hammock and an electrical blast surged through the man, blowing off the bottom of his shoes. Inexplicably, the lightning cured his cancer.

·       Creating temporary tattoos:  ‘lightning flower’ or ‘lightning tree’ is a reddish feathery or fern-like fractal pattern sometimes seen on the neck or torso of lightning victims. The marks are temporary and usually appear within an hour or two of being struck. The marks are formed due to capillary damage and vary from person to person.

·       “Weird, strange, and unbelievable” sounds known as whistlers were first detected by a listening station aboard the US Navy icebreaker Atka in the ’50s. They had a musical quality, described as a high- to low-pitched tone resembling a partial wolf whistle, and they originate when lightning discharges emit electromagnetic waves in the atmosphere. The waves travel along lines of force in Earth’s magnetic field, circle the planet in seconds, and return to the point of origin (hence the descending pitch). These sounds can be picked up with a special receiver and a long antenna.

Read a related article from NBC News about what a lightning strike might do to your skin.  Click here.

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The Correct Way to Estimate Lightning Strike Distance

The 30/30 Rule

Many of us have heard that if you determine the lightning distance from you to a strike by counting the number of seconds between hearing thunder and seeing a lightning strike, that is how far away in miles the lightning is (not true). This notion is actually called “flash-to-bang” method because of the time between seeing and hearing lightning.  Flash-to-bang is real, but not in the way we have traditionally believed.

Statistics show that the majority of people who are struck by lightning are struck before or after a thunderstorm, not during it. Given that lightning injuries often last a lifetime, it is wise to know with scientific accuracy just how far away lightning really is from where you are when a thunderstorm is clearly present.

Lightning comes first and subsequently, thunder.  Seeing and hearing lightning and thunder can be used to protect yourself and others if you understand the 30/30 Rule.  The first 30 is 30 seconds.  If it takes less than 30 seconds to hear thunder after seeing a lightning flash, the probability of being struck by lighting is great because the lightning is within 6 miles of your location. At this time one should seek proper shelter from the storm and remain in that shelter for 30 minutes (the second 30) after hearing the last thunder.

The Correct Method to Calculate Lightning Distance

The following table is the correct Flash-to-Bang estimations calculated based on the speed of sound at sea level:


If thunder is heard The lightning is . . .
5 seconds after a flash 1 mile away
10 seconds after a flash 2 miles away
15 seconds after a flash 3 miles away
20 seconds after a flash 4 miles away
25 seconds after a flash 5 miles away
30 seconds after a flash 6 miles away

NOAA and the National Weather Service recommend seeking immediate shelter when lightning is 6 miles or less of your location.  To download a free copy of our wallet-sized lightning safety card click HERE.

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