Auroras, also known as northern lights or the aurora borealis, were visible throughout the San Francisco Bay Area on Friday night and early Saturday morning and were reported as far south as San Diego. The rare occurrence was due to a phenomenon known as a solar storm.

Graded as a Level 4 storm (out of 5), it marked the first severe geomagnetic storm that the National Oceanic and Atmospheric Administration has tracked in nearly 20 years.

Starting around 11 p.m. on Friday night, incredible pinkish-purple hues could be seen around the San Francisco Bay Area. A number of Instagram users sent in stunning photos of the lights above Bay Area landmarks, such as the Golden Gate Bridge and the Altamont Pass windmills. 

Some social media users even reported seeing the northern lights from Los Angeles and San Diego counties. 

The lights were even more intense in areas further north, such as Lake Berryessa in Napa County and Middletown in Lake County. 

SFGATE California parks editor Ashley Harrell captured the lights illuminating the sky above from Humboldt County.

Gerald McKeegan, a Chabot Space & Science Center astronomer, detailed what happens during a solar storm to SFGATE on Thursday. According to McKeegan, charged particles burst millions of miles out into space and meet the Earth’s magnetic field before getting deflected toward the poles of our planet, where they enter the atmosphere and produce the glowing, shimmering clouds we know as the northern lights.

Along with the incredible visuals, the intensity of the solar storm also brought electrical issues. On Saturday, NOAA said on social media that there had been “reports of power grid irregularities and degradation to high-frequency communications and GPS.”

“It’s just Mother Nature reminding us who’s boss,” said McKeegan on Thursday.

The northern lights could be visible again tonight, with NOAA warning the geomagnetic storm is expected to last until at least Sunday.

SFGATE senior reporter Amanda Bartlett contributed to this story.