What different heat alerts mean and tips to stay cool during a heat wave

Significant heat wave moves through Metro Detroit next week

Fan (Pixabay)

4Warn Weather – The first significant heat wave of the year is moving into Metro Detroit next week.

The air temperature and the humidity will make the heat index values soar into the 90s and lower 100s. With this in the forecast, it’s a good time to review what to do when the thermometer soars that high.

What the different heat alerts mean

Heat advisory: A heat advisory is issued within 12 hours of the onset of extremely dangerous heat conditions. The general rule of thumb for this advisory is when the maximum heat index temperature is expected to be 100 degrees or higher for at least 2 days, and nighttime air temperatures will not drop below 75 degrees.

These criteria vary across the country, especially for areas that are not used to dangerous heat conditions. Take precautions to avoid heat illness. If you don’t take precautions, you may become seriously ill or even die.

Excessive heat watch: Excessive heat watches are issued when conditions are favorable for an excessive heat event in the next 24 to 72 hours. A watch is used when the risk of a heat wave has increased but its occurrence and timing is still uncertain.

Excessive heat warning: An excessive heat warning is issued within 12 hours of the onset of extremely dangerous heat conditions. The general rule of thumb for this warning is when the maximum heat index temperature is expected to be 105 degrees or higher for at least two days and nighttime air temperatures will not drop below 75 degrees.

These criteria vary across the country, especially for areas not used to extreme heat conditions. If you don’t take precautions immediately when conditions are extreme, you may become seriously ill or even die.

Heat safety tips

Heat safety tips: Protecting yourself from heat and sun. (WDIV)

You need to drink enough water to prevent heat illness. An average person needs to drink about 3/4 of a gallon of water daily. Everyone’s needs may vary.

  • Make sure that you are getting enough water by noting your urine color. Dark yellow may indicate you are not drinking enough.
  • Avoid sugary, caffeinated, and alcoholic drinks.
  • If you are sweating a lot, combine water with snacks or a sports drink to replace the salt and minerals you lose in sweat.
  • Talk to your doctor about how to prepare if you have a medical condition or are taking medicines.

Make a plan to stay cool

Heat and safety tips: Stay indoors during heat waves. (WDIV)

Do not rely only on electric fans during extreme heat. When temperatures are in the high 90s, fans may not prevent heat-related illness. Taking a cool shower or bath or moving to an air-conditioned place is a much better way to cool off.

  • Spending a few hours each day in air conditioning can help prevent heat illness.
  • If you have air conditioning, be sure that it is in working order.
  • If you do not have air conditioning or if there is a power outage, find locations where you can stay cool. For example, a public library, shopping mall, or a public cooling center. Plan how you will get there.
  • Additional resources may be available from local government or community groups.
  • Make sure you have plenty of lightweight, loose clothing to wear.
  • Create a support team of people you may assist and who can assist you. Check in with them often to make sure that everyone is safe.
Heat safety tips: When working outdoors in extreme heat. (WDIV)

What to do before an extreme heat event

  • Make sure you have food at home, extra water, and any needed medications
  • Make a list of family and friends you may need to check on during the extreme heat event
  • Know where your local cooling shelter is located
  • Reschedule any outdoor events if necessary

What to do during an extreme heat event

  • Stay in the air conditioning and out of the sun, if possible
  • Check on friends, family, neighbors, and pets
  • Drink plenty of water if outdoors in the sun
  • Take frequent breaks if working outside
  • Wear lightweight, loose-fitting, light-colored clothing to help reflect the sunlight instead of absorbing it like dark colored clothing does

Stay with WDIV Local 4 News and the 4Warn Weather Team for the latest on this significant heat wave moving through Southeastern Michigan.


About the Author

Bryan became a permanent member of the 4Warn Weather Team in March 2023 after coming to Local 4 in May 2022 as a freelance meteorologist.

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