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Heat safety information from the National Weather Service


Minnesota's Third Deadliest Weather Factor Since 1990...
The third greatest number of weather fatalities in Minnesota since 1990 has been due to excessive heat. Eighteen people have died from high heat and humidity. Only tornadoes and flooding have killed more people in the last 30 years.

Wisconsin's Deadliest Weather Factor Since 1982...
The greatest number of weather fatalities in Wisconsin since 1982 has been due to excessive heat. 134 people have died from high heat and humidity. This total is more than tornadoes, flooding, blizzards or anything else. The 1995 summer heat waves hold the record as the number one weather-related killer in Wisconsin since it became a state in 1848. Most deaths occurred in the major urban areas in southeast Wisconsin, but there have been a number of fatalities in the rest of the state as well.

In the last 10 years, a national average of 219 people have died as a result of health problems directly related to excessive heat. Considering this death toll, the National Weather Service has stepped up its efforts to more effectively alert the general public to the hazards of heat waves.

Based on research findings, the National Weather Service devised the Heat Index (HI). It is an accurate measure of how hot it really feels when the relative humidity is added to the actual air temperature. It is important to note that since heat index values were devised for shady, light wind conditions, exposure to full sun can increase values by up to 15 degrees.

The wet bulb globe temperature (WBGT) has become a very important consideration for many organizations that deal with outdoor sports, work and more. Information about the WBGT can be found at:

Heat disorders generally have to do with a reduction or collapse in the ability of the body to shed heat by circulatory changes and sweating. In other words, a chemical imbalance caused by too much sweating. When heat gain exceeds the level the body can remove, or when the body cannot compensate for fluids and salt lost through perspiration, the inner-core temperature of the body begins to rise and heat-related illnesses may develop. Ranging in severity, heat disorders share one common feature: the individual has over-exposed or over-excerised for his/her age and physical condition in the existing thermal environment.

Sunburn, with its ultraviolet radiation burns, can also significantly retard the ability of skin to shed excess heat.

Safety tips...
The National Weather Service will issue advisories or warnings when the heat index is expected to have a significant impact on public safety. The common guidelines for the issuance of excessive heat warnings is when the maximum daytime index is expected to reach 105, and the nighttime low temperature does not fall below 75 or 80 degrees.

Here are some tips to follow to ensure that heat-related problems do not impact you...

  • Slow down. Strenuous activities should be reduced, eliminated or rescheduled to the coolest time of the day. Individuals at risk should stay in the coolest available place, not necessarily indoors. Dress for summer. Lightweight, light-colored clothing reflects heat and sunlight and helps your body maintain normal temperatures.
  • Put less fuel on your inner fires. Foods such as proteins that increase metabolic heat production also increase water loss.
  • Drink plenty of water or other non-alcoholic fluids. Your body needs water to keep cool. Drink plenty of fluids, even if you don't feel thirsty. However, those who suffer from epilepsy, heart, kidney or liver disease, are on fluid restrictive diets, or have a problem with fluid retention should consult a physician before increasing their consumption of fluids.
  • Do not drink alcoholic beverages.
  • Spend more time in air-conditioned places. Air conditioning in homes and other buildings markedly reduces danger from the heat. If you cannot afford an air conditioner, spending time each day in an air-conditioned environment during hot weather affords some protection.
  • Be careful not to get too much sun. Sunburn makes the job of heat dissipation that much more difficult.


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