Hairy, wig-like ice formations discovered on Washington trails. But what causes them?

No, Washington hikers aren’t finding wigs dropped in the middle of the woods. It’s just ice.

Hikers are discovering fluffy, hair-like formations along trails. The weird phenomenon makes ice grow along logs and it looks like a pile of fur or a serving of cotton candy.

Some hikers have mistaken the ice for fungus because of its unique shape, according to the Washington Trails Association.

The formation has been called “hair ice,” and it takes nearly perfect conditions to form. It grows on rotten branches of some trees when certain fungi is present, fungi which influence the shape of the ice crystals that form, according to the European Geosciences Union.

“Simply speaking, hair ice is formed when moisture fizzes from a bit of wood and instantly freezes, creating delicate, angel-hair-like strands in mid-air,” the Trail Association wrote.

It’s not rare, but it can be hard to spot.

“To see hair ice, one’s best chance is to hike into a broadleaf forest between the latitudes of between 45° and 55° N on a cold morning,” Smithsonian Magazine reported. “There, amid patches of snow and frost, a keen eye might spot delicate crystals extending from wood in filaments about 0.01 millimeters thick — about the diameter of a human hair.”

In Washington, hair ice has been spotted on the Lime Kiln Trail near Granite Falls and in Federation Forest State Park, according to the Trails Association. People on social media have reported seeing it near Mill Creek Nature Preserve and in Maple Valley, Franklin and Port Orchard.

This story was originally published January 25, 2021 at 11:31 AM with the headline "Hairy, wig-like ice formations discovered on Washington trails. But what causes them?."