Extreme Temperature Safety

Home >> Perils >> Extreme Temperatures

The weather affects everything on earth. So does the temperature. Intense summer heat may help to ignite dry grass and trees causing widespread wildfires that threaten homes and families. 

In cold weather, heavy snow falls can make it difficult to do anything outside -- travel to work or school or the store for supplies. 

Both extreme weather conditions -- a winter freeze or a heat wave -- can put individuals and families at risk. Remember the old saying, "Expect the best but prepare for the worst." That old saying could save lives.

Winter Storms

Winter storms derive their energy from the clash of two air masses of very different temperature and moisture levels. In North America, winter storms typically form when an air mass of cold, dry Canadian air moves south and interacts with a warm, moist air mass moving north from the Gulf of Mexico.

Over North America, strong winds blowing from west to east usually move a winter storm quickly across the continent. That's why a winter storm rarely lasts more than a day in one area.  

One exception to this rule occurs downwind of major bodies of water like the Great Lakes. If a strong, cold wind blows over a great length of unfrozen water, the air can acquire a substantial amount of moisture. This moisture turns into heavy snow when it reaches land. These "lake-effect" snowstorms can last for many days and dump huge amounts of snow. 

The Dangers of Winter Storms

Heavy snowfall and extreme cold can immobilize an entire region. Even areas that normally experience mild winters can be hit with a major snowstorm or extreme cold. The impacts include flooding, storm surge, closed highways, blocked roads, downed power lines and hypothermia. You can protect yourself and your home from the many hazards of winter by planning ahead.

Understand these terms used by forecasters concerning winter weather: 

  • Freezing rain -- Rain that freezes when it hits the ground, creating a coating of ice on roads, walkways, trees and power lines.
  • Sleet -- Rain that turns to ice pellets before reaching the ground. Sleet can also cause roads to freeze and become slippery.
  • Winter Storm Watch --A winter storm is possible in your area.
  • Winter Storm Warning -- A winter storm is occurring, or will soon occur in your area.
  • Blizzard Warning -- Sustained winds or frequent gusts to 35 miles-per-hour or greater and considerable falling or blowing snow (reducing visibility to less than a quarter mile) are expected to prevail for a period of three hours or longer. 
  • Frost/Freeze Warning -- Below freezing temperatures are expected.

Heat Waves

Generally, extreme heat is defined as temperatures that hover 10 degrees or more above the average high temperature for the region that last for prolonged periods of time and are accompanied by high humidity that the body cannot tolerate. 

The Dangers of Extreme Heat

A heat wave is a very dangerous situation. People living in urban areas may be at greater risk from the effects of a prolonged heat wave than people living in rural regions. It is dangerous for those with respiratory difficulties, which can worsen when stagnant atmospheric conditions trap pollutants in urban areas, adding unhealthy air to excessively hot temperatures. In addition, asphalt and concrete store heat longer and gradually release heat at night, which produces significantly higher nighttime temperatures.

Extreme heat and the body heat can kill by pushing the human body beyond its limits. Under normal conditions, the body's internal thermostat produces perspiration that evaporates and cools the body. However, in extreme heat and high humidity, evaporation is slowed and the body must work extra hard to maintain a normal temperature.  

The duration of excessive heat plays an important role in how people are affected by a heat wave. Studies have shown that a significant rise in heat-related illnesses happens when excessive heat lasts more than two days. Spending at least two hours per day in air conditioning significantly cuts down on the number of heat-related illnesses.

Who Is at Risk From Extreme Heat?

Everyone is at risk from heat, especially the elderly, very young and those who work outdoors. 

Because men sweat more than women, they are more susceptible to heat illness because they become more quickly dehydrated.


Signs of Heat Exhaustion

  • Cool, moist, pale, or flushed skin

  • Heavy sweating

  • Headache

  • Nausea

  • Vomiting

  • Dizziness

  • Exhaustion

  • Body temperature may be normal, or is likely to be rising

Signs of Heat Stroke

  • Hot, red skin

  • Changes in consciousness

  • A rapid, weak pulse

  • Rapid, shallow breathing

  • A very high body temperature -- sometimes as high as 105 degrees F.

  • If the person was sweating from heavy work or exercise, skin may be wet; otherwise, it will feel dry