As people in Japan braced for a powerful typhoon Friday night, they looked up to see a strange phenomenon: a bright purple sky. Typhoon Hagibis brought heavy rain and strong winds to the region and is expected to be Japan's worst in six decades.

The typhoon touched down southwest of Tokyo on Saturday. An earthquake shook the area shortly before landfall.

As hundreds of thousands of people were ordered to evacuate, residents posted images of the bright purple and pink sky on social media.

Get Breaking News Delivered to Your Inbox

"Beautiful sky in Japan before the typhoon. Looks peaceful but it's actually an indicator that the storm is coming #PrayForJapan," one Twitter user wrote.

The phenomenon has occurred several times in the U.S. following major hurricanes. Meteorologists say the beautiful skies are a result of "scattering."

"As sunlight shines down to Earth, most of the colors of the spectrum are able to reach the surface uninterrupted," meteorologist Lauren Rautenkranz explained after Hurricane Michael in 2018. "But the shorter wavelengths, blue and violet, are scattered in every direction. This light bounces from particle to particle until it eventually reaches your eyes. But the sky doesn't appear violet and blue because of our eyes' limitations."

Under normal conditions, our eyes can only detect blue, but during a storm, purple can sometimes become visible.

"The light was scattered around the moisture in the air, causing the magical purple color," she said.

The storm is far from over. Flooding was reported Saturday south of Tokyo. Rivers have swelled and boats have flipped. Mudslide warnings have also been issued.

At least one person is confirmed dead. A man died after a tornado flipped over his car.