By Skip Rigney

There is still no cool front in our future, at least until next weekend at the earliest. A tropical disturbance now in the Caribbean Sea could affect us by mid-week, but uncertainty is high regarding the system’s strength and track.

So, instead of discussing once again summer’s refusal to leave us, I want to look skyward to a part of the atmosphere that we often don’t think about, but which could one day disrupt the lives of hundreds of millions of people, including us.

Typically I write about what is going on in the lowest layer of the atmosphere, which scientists call the troposphere. This is where we find the weather and clouds that we experience.

Even when I write about what is happening in the “upper” atmosphere, for example the jet stream, I am actually talking about the upper portion of the troposphere. In the southern United States, the troposphere is usually 8-9 miles thick during the summer, and a mile or two thinner in the winter.

But there are a number of layers of the atmosphere above the troposphere. One called the ionosphere extends from an altitude of about 40 miles upward to over 500 miles. Interaction with radiation from the sun causes the ionosphere to become electrically charged.

The amount of charge and the distribution of electrically-charged particles vary depending on whether it’s day or night, and also due to variations in the energy coming from the sun. These variations are “space weather.”

And, why should we care?

Because, one day, the Global Positioning System (GPS) that allows you to get driving directions on your mobile phone, and helps the the U.S. military place missiles on their targets, may suddenly go haywire because of a severe disturbance in the ionosphere.

Such a disturbance, known as a geomagnetic storm, could also disrupt and damage the electrical power grid causing partial or complete blackouts.

Space weather events such as geomagnetic storms “have the potential to disrupt electric power systems; satellite, aircraft, and spacecraft operations; telecommunications; position, navigation, and timing services; and other technologies and infrastructures that contribute to the Nation’s security and economic vitality,” according to the National Space Weather Action Plan written in 2015 by a special White House task force.

Severe geomagnetic storms are relatively rare events that occur when the sun produces unusually powerful solar flares or similar solar disturbances.  When the solar energy and the particles associated with those events hit the ionosphere, the resulting geomagnetic storm can wreak havoc here on Earth.

In July 2012 a major solar eruption ejected a blob of energy and charged particles that barely missed the earth, according to a study led by Daniel Baker of the University of Colorado. NASA, using data from a study by the National Academy of Sciences, concluded that if it had hit the earth, damage to the power grid could have been in the trillions of dollars.

A geomagnetic storm in March 1989 knocked out the power in the entire Canadian province of Quebec, leaving millions shivering in subfreezing temperatures for nearly nine hours. If potentially dangerous space weather threatens, watches and warnings will be distributed through the news media from the National Weather Service’s Space Weather Prediction Center.

The center has been monitoring and forecasting space weather since its creation in 2007.