SNOWFLAKE, Ariz. (CBS Local) — Lights from a medical marijuana farm filled the sky over Snowflake, Arizona, with a bright purple glow on a recent foggy morning.

Cara Smith was on her way to work at Copperstate Farms, the largest medical marijuana wholesaler in the state, on Friday morning when she noticed the strange phenomenon. She took a picture of the scene about 6:30 a.m.

“The purple lights are always there but don’t usually light up the sky like this,” she told CNN. “It had snowed that morning and was still very foggy and cloudy.”

Snowflake is in Navajo County, Arizona, about 175 miles northeast of Phoenix. The county posted Smith’s photo on its Facebook page.

“The purple glow is a result of UV lights from nearby medical marijuana farm Copperstate Farms and the snow clouds overhead,” the post said.

Copperstate Farms, which includes 40 acres of greenhouses, uses a combination of red and blue ultraviolet lights that are used to help grow pot plants, according to a company spokeswoman.

The light reflected off the snow on the ground, lighting up the clouds above, The Weather Channel reported.