By Chris Spears

DENVER (CBS4) – You probably don’t think about travel delays if it’s hot, sunny and dry outside. But as summer heat gets extreme, those delays can happen to those traveling by land or air.

When it comes to flying, one potential problem can arise at take-off, especially for the pilot of a fully-loaded jet. It can be difficult to get a plane off the ground when temperatures climb as high as the 100s.

(credit: CBS)

To understand this we need a quick lesson in physics. Specifically a lesson about air density. To visualize this let’s think about the air over a city like Denver as a column.

When temperatures are cold the air is dense, making the column short and compact. Air is the densest near the ground and that is good for a plane at takeoff. The colder the air, the more efficient a plane is at climbing. A fully loaded jet can leave the ground in less than 30 seconds.

(credit: CBS)

But it’s the opposite when it’s hot outside. Air rises up from the ground making the column very tall. This makes the air near the surface very thin, which is a problem for a pilot on takeoff. The thin air impacts the lift that a plane needs to leave the ground. To overcome this, a pilot will need more time to reach a higher speed for takeoff and that requires extra-long runways.

The weight of a plane is also a factor in this equation. Occasionally flights will need to remove cargo, luggage and even passengers to make a safe takeoff possible. In Denver, we have an extra added problem due to our altitude. The air here is already about 15% thinner than it is for locations at sea level.

(credit: CBS)

If traveling by land, you need a vehicle that is in sound mechanical shape with good tires when it is really hot outside. If air temperatures hit the upper 80s or higher, concrete and asphalt surfaces can reach as high as 150 degrees or more. The heat of the pavement combined with added heat from friction, especially when traveling at a high rate of speed, can make tire blowouts become a real possibility.

Chris Spears