Deadly heat is descending on us. Here’s what you need to know

By Ben Tobin
Louisville Courier Journal

The National Weather Service has issued an excessive heat warning for the Louisville area and much of the state through Sunday evening.

Hot temperatures and high humidity will combine “to create a dangerous situation in which heat illnesses are possible,” according to the National Weather Service.

According to Dr. Jeffrey Howard, the Kentucky Department for Public Health commissioner, “serious injury and even death – particularly for children and older adults exposed to extreme levels of heat – can occur.”

“During summer, we often spend long periods of time outside,” Howard said. “However, with warmer extreme temperatures comes the risk of overexertion, so we advise the public to take steps to keep cool and prevent harm.”

National Weather Service meteorologist John Gordon warned at a press conference Thursday that heat, along with cold, is a “silent killer.” From 2009 to mid-July of 2019, there have been 94 heat-related deaths due to inclement weather in Kentucky, according to statistics provided by the Kentucky Department for Public Health.

Here is what you need to know.

How hot is it going to be?

A better question is how hot is it going to feel. The weather service is warning that the heat index — what the temperature feels like to the human body when relative humidity is combined with the air temperature — will range from 100 to 110 degrees. So while the air temperature may be 95 to 97 degrees, as has been forecast this weekend, the relative humidity will make it feel hotter. A heat index of 110 degrees would actually be hotter than what it will feel like in Death Valley this weekend. 

And here’s something even scarier. The heat index only measures how hot it will feel in the shade. If you’re in direct sunlight, you can add up to 15 degrees, National Weather Service meteorologist Evan Webb said. 

What are the health concerns?

A heat index of 100 to 110 degrees could increase your chances of heat stroke, cramps or heat exhaustion, according to the weather service.

Heat stroke is the most serious and can cause death or permanent disability. Heat stroke occurs when the body is unable to cool down — meaning you can’t sweat anymore, according to the Centers for Disease Control.

And the higher the humidity, the hotter your body feels, which causes you to sweat.

When the heat index reaches 125 degrees, heat stroke becomes highly likely, the weather service says.

The very young, the elderly, those without air conditioning and those participating in strenuous outdoor activities will be the most susceptible, the weather service warns.

Related: ‘Oppressive’ humidity coming to Louisville with a heat index above 100

Don’t leave children in the car

Never — to repeat for emphasis, never — leave your pets or children alone in parked vehicles. Car interiors can reach “lethal temperatures in a matter of minutes,” the Weather Service said, adding: “Remember to check the back seat!”

Between 1998 to 2018, 20 children died of vehicular heatstroke in Kentucky after being left in hot cars, according to NoHeatStroke.org. Though no deaths have occurred in Kentucky so far this year, 21 children have died nationwide due to being stuck in a heated vehicle.

What are the symptoms of heat stroke and heat exhaustion?

The symptoms of heat stroke include:

Confusion, altered mental status, slurred speech
Loss of consciousness (a coma)
Hot, dry skin or profuse sweating
Seizures
Very high body temperature

If you witness someone suffering from a possible heat stroke, the CDC advises that you call 911, stay with the person and move them to a cool area while removing outer clothing. You should also cool them with cold water, ice bath or cold wet cloths if possible. Cold wet cloths or ice should be placed on the head, neck, armpits and groin. 

Symptoms of heat exhaustion include headache, nausea, dizziness, weakness, irritability, thirst, heavy sweating, elevated body temperature and decreased urine output.

What should you do to protect yourself?

Louisville Metro Emergency Services spokesman Mitchell Burmeister says folks should wear light and loose clothing, stay in the shade, take extra breaks if working outdoors and drink plenty of water. People should also protect against sunburn and take it easy during the hottest parts of the day, if possible.

Multiple days of heat make it worse

Asiaha Allen, Ayrihana Allen and Sanchez Brown tried to cool off in the water of the Ohio River at the Falls of the Ohio State Park in Clarksville Thursday afternoon as temperatures rose to the mid 90s. The girls said the water was too warm to offer much relief as the explored. A heat wave is expected to cook the local area through Sunday.

Historically, Kentucky has had an average of six days per year with a heat index above 100 degrees, according to a recent study by the Union of Concerned Scientists.

So far this year, the Louisville area has had a heat index at or above 100 degrees for only six hours, according to a tool from the North Carolina Climate Office that allows users to search historic heat indexes nationwide.

But the weather service warns that several days of heat indices near or above 105 could have a cumulative impact on some people, particularly those who work outside. And its warning lasts four days.