With warm weather comes warning about kids left in cars

We all are familiar with extreme natural weather events like tornadoes and hurricanes that result in injuries and deaths. But pediatric vehicular heatstroke (PVH) is a lesser known weather-related killer.

The victims are children who succumb to extreme hyperthermia when left unattended in closed motor vehicles.

The physical process that heats up the interior of a vehicle is known as the greenhouse effect. The sun emits shortwave energy, and objects that absorb shortwave energy emit long wave energy. Fortunately for greenhouses but unfortunately for closed vehicles, the long wave energy does not pass through windows and effectively heats the air inside.

A controlled study of closed vehicle interior temperature conditions shows that the rate of heating compared to the outside ambient temperature is very rapid. On sunny days with outside temperatures of 70 degrees or greater, interior temperatures rose by nearly two degrees per minute for the first 20 minutes.

Within one hour, a 70-degree outside temperature became 113 inside a closed car. On a 90-degree day, the interior temperature climbed to 133.

Opening windows a few inches did little to mitigate the greenhouse heating effect, because there is only a minimal amount of air exchange.

Over the last 21 years, more than 800 PVH deaths occurred in the United States alone. The saddest part of this story is that each death is preventable.

Statistics show that nearly three-quarters of PVH fatalities happen because an adult caregiver exited a vehicle, leaving a child behind. Most of the remaining tragedies involved children climbing into vehicles to play or hide.

Some researchers believe that rear-facing child car seats in the back seats of vehicles contribute to PVH instances, because the child becomes “invisible” to the driver. Rear seat child restraints became popular when air bags became standard vehicle equipment. Deployed air bags proved to be dangerous to infants and toddlers secured in front-facing restraints in the passenger seat.

Post-tragedy interviews show that the “invisible child” scenario sometimes occurs when a caregiver has a change of routine and a child destined for daycare is not dropped off. Some caregivers intentionally leave a child alone inside a car, but that is less common. These individuals are unaware, or unconcerned, about the consequences of their behavior.

It is important to remember that PVH tragedies occur even during relatively cool days. Last summer, an infant died in Moraga when the outdoor temperature was 81 degrees.

Caregivers should develop a “look before you lock” mantra to ensure children are not forgotten. One suggestion is to keep a stuffed animal in your child’s car seat and transfer it to the front seat while the child is in the car to remind you of the precious cargo in the back seat.

Also, always lock your vehicle, even in your own driveway, to prevent unattended children from entering.

Pets are not exempt from hyperthermia when they are left in vehicles, even if their noses protrude from a slightly open window.

Woody Whitlatch is a meteorologist retired from PG&E. Email your questions or comments to