|The graph above is courtesy of San Jose State University, which offers more details on how these deaths occured, age of victims, etc. Use of this graph does not imply NWS endorsement of services provided by San Jose State University. |
Never leave children, disabled adults or pets in parked vehicles!
Each year, dozens of children and untold numbers of pets left in parked vehicles die from hyperthermia, which occurs when the body absorbs more heat than it can handle. Hyperthermia can occur even on a mild day with temperatures in the 70s. Studies have shown that the temperature inside a parked vehicle can rapidly rise to a dangerous level for children, pets and even adults. Leaving the windows slightly open does not significantly decrease the heating rate. The younger the child the more severe the effects because their bodies have not developed the ability to efficiently regulate its internal temperature.
How fast can the sun heat a car?
The sun's shortwave radiation (yellow in figure below) heats objects that it strikes. For example, a dark dashboard or seat can easily reach temperatures in the range of 180 to over 200°F. These objects (e.g., dashboard, steering wheel, child seat) heat the adjacent air by conduction and convection and also give off longwave radiation (red in figure below) which is very efficient at warming the air trapped inside a vehicle. Shown below are time lapse photos of thermometer readings in a car over a period of less than an hour. As the animation shows, in just over 2 minutes the car went from a safe temperature to an unsafe temperature of 94.3°F. This demonstration shows just how quickly a vehicle can become a death trap for a child.
Objects Heated by the Sun Warm Vehicle's Air
Heat deaths in autumn, winter and spring
Hyperthermia deaths aren't confined to summer months. They also happen during the spring and fall. Below are just a few of MANY tragedies.
Adults also are susceptible to hyperthermia in vehicles. On July 12, 2001, a man died of heat stroke after falling asleep in his car with the windows rolled up in the parking lot of a supermarket in Hinds County, MS.