What is the aurora borealis caused by?

According to the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center, a series of solar flares and coronal mass ejections from the sun are anticipated to create stunning auroras visible as far south as Alabama and Northern California. However, along with this celestial spectacle, disruptions in communications on Earth are expected tonight and over the weekend.

The center, a division of the National Weather Service, reported extreme geomagnetic storm conditions at 6:54 p.m. ET on Friday evening, reaching a severity level of 5 out of 5. The last time Earth experienced a solar storm of this magnitude was in October 2003, resulting in power outages in Sweden and damaged power transformers in South Africa.

Scientists at the center first detected signs of a severe geomagnetic storm, rated level 4, at 12:37 p.m. ET when a major disturbance was noted in Earth’s magnetic field. This event follows the issuance of a geomagnetic storm watch on Thursday evening, the first such watch since January 2005.

The center’s space weather scale encompasses three categories: solar flares causing high-frequency radio blackouts, geomagnetic storms, and solar radiation storms.

Shawn Dahl, the service coordinator for the Space Weather Prediction Center, indicated that the current solar activity could result in a solar radiation storm, albeit at the lower end of the scale. This level of activity may affect rocket launch operations and satellite communications, but no significant disruptions are anticipated at this stage.

The peak of geomagnetic storm activity for Earth is forecasted to occur between 2 a.m. and 5 a.m. ET on Saturday. The center describes this event as “an unusual event,” as severe geomagnetic storms have been rare in recent years.

Geomagnetic storms, triggered by coronal mass ejections directed at Earth, can cause major disturbances in Earth’s magnetic field, potentially impacting infrastructure both in near-Earth orbit and on the planet’s surface. Operators of critical systems have been alerted to the potential impacts, including the possibility of increased voltage control problems, anomalies in satellite operations, and GPS degradation.

While auroras may not always be visible overhead depending on the location, experts advise observing the horizon for a colorful display. Even if auroras aren’t directly visible, capturing images of the sky with smartphones may reveal the spectacle. Michael Liemohn, a professor at the University of Michigan, suggests that residents in southern Michigan may witness the aurora and advises moving away from city lights for optimal viewing conditions.

The Space Weather Prediction Center urges preparedness for potential power outages, suggesting keeping batteries and a weather radio on hand. However, disruptions to internet and cellphone service are not anticipated, and any interference with GPS is expected to be short-lived.