The Storm of the Century

September 2 marks the anniversary of one of the most powerful storms ever recorded on Earth. It was on this date in 1859 that a tremendous geomagnetic storm slammed into our planet.

A day earlier, on the morning of September 1, a magnetic explosion on the sun sent a huge solar flare composed of an estimated two billion tons of charged particles toward Earth. This gigantic coronal mass ejection (CME) entered the atmosphere just before dawn on September 2, causing the Earth’s magnetic field to literally bend and quiver. Enormous electrical currents surged through the atmosphere, and brilliant auroras were seen as far south as Hawaii and Cuba. In fact, the pre-dawn auroras were reported to be so bright that residents in Colorado could read their newspapers as easily as during daylight.

This intense geomagnetic storm also crippled telegraph service across the globe. Sparks discharged through telegraph equipment and set paper on fire in telegraph offices. It took more than a week for the planet’s magnetic field to return to equilibrium.

As luck would have it, British astronomer Richard Carrington, regarded as one of England’s best solar astronomers, was observing sunspots projected onto the wall of his observatory the moment the solar flare erupted. The entire solar flare episode lasted only five minutes, but its observation marked the beginning of what today is known as the field of space weather.

Even with satellites constantly monitoring the sun, the Earth is surprisingly vulnerable to strong geomagnetic storms. Our interconnected power grids could easily be crippled by a strong geomagnetic storm, through what scientists and emergency managers call “cascade failures.”

In fact, a geomagnetic storm much weaker than the 1859 storm knocked out power to Quebec, Canada, for nine hours in March 1989. A stronger storm in May 1921 produced ground currents estimated to be ten times stronger than the 1989 storm that shut down Quebec — and this 1921 storm is estimated to have been only half as strong as the Carrington Event of 1859.

A new National Academy of Sciences report, “Severe Space Weather Events — Understanding Societal and Economic Impacts,” tries to answer the question of what could happen if a super solar flare similar to the one in 1859 hit Earth today. The conclusions are scary.

According to the report, the economic impact to our infrastructure in the first year after a powerful geomagnetic storm could reach $2 trillion. As the storm hit Earth, widespread power outages would occur, along with radio and telecommunications failures. Banking, transportation and satellite navigation all would be affected. While some equipment would come back online as the storm passed, other equipment (such as transformers and power generators) could be destroyed, and might take months to replace or repair.

But there are steps we can take to limit the damage a powerful geomagnetic storm could cause. These include reducing some of the interconnected areas on power grids that criss-cross the globe, improving radio codes and frequencies, and developing better forecasting techniques to provide better advance warning of an approaching storm.

NASA has several spacecraft in orbit around the Earth monitoring solar flares and radiation. In addition, other probes are on missions to the sun to take a closer look. The data from these projects goes to NOAA’s Space Weather Prediction Center, which is the national office charged with forecasting potential solar and other celestial events that might affect Earth.

There’s no question that strong geomagnetic storms will hit Earth. The main question is, will we be ready? With every piece of new data, the answer is coming closer to “yes.”