Mark Spence was watching the storm approach when he saw it crawling along 57th Street S.

A foot and a half wide and growing, the black mass collected earthy matter and picked up speed as it rolled by.

He yelled for his teenage daughter Taryn to come quick.

"I knew as soon as I saw it what it was," she said.

Hair.

Specifically, hair extensions, those ubiquitous — and expensive — fashion accessories that have transformed hairstyles from Hollywood to high schools. But so many of them, detached from the heads of their owners, are appearing on sidewalks, in parking lots and in mall bathrooms that they have earned their own name: tumbleweaves.

"They are not occasional," said Mark Spence, 47, who has seen at least four other weaves abandoned in and around Gulfport. "They just pick stuff up along the way. I don't know how they do it."

The phenomenon is not limited to Florida.

Internet blogs named Gurl, There Goes Her Tumble Weave! and girlyoulostyourweave.com host hair street photography from across the country. Tumbleweaves tangled with leaves, twigs and sometimes feathers. There are "drag droppings" and "Happy Halloweave" hot pink braids. An auburn wig someone named "Old Red." One poster mistook a large black hairpiece for a fuzzy cat ("It did not meow," he wrote). A blond "honey badger weave" was spotted "sashaying away from the trash bag" on a city street. One weave was found attached to a diaper. As tumbleweaves.org eloquently states, "Sometimes good hair gets kicked to the curb."

There are many ways women can lose track of their locks, said Falon Billups, who has been a hairstylist for 13 years and owns a Tampa salon, Dream Weave Hair Gallery. Often the weaves or extensions weren't installed properly. Sometimes they're tugged loose, Billups said, while couples are, ahem, "doing their thing." Commonly, abandoned hair litters the ground after girl fights.

Weaves and extensions don't come cheap, ranging from $50 to more than $1,000. And often hairstylists aren't able to perform weave patchwork. "Usually you end up paying for the whole procedure," Billups said.

If it's so expensive, why do women leave them on the ground?

"You don't want everybody to know your hair is falling out," Billups said, laughing.

Jack Sweeney, 45, who rode with the Seminole Heights Bicycle Club in Tampa for eight years, said stray hair became just another road hazard, like potholes and car doors.

"Watch the weave!" he said riders would shout to each other. "If it gets tangled up in your chain, it's really difficult to get out."

He has since moved to Maryland and has noticed only one tumbleweave.

"Oh, my gosh," he said to his kids. "It's a whole bunch of dead snakes."

"Dad," they replied, gesturing to the pile of dreadlocks, "it's hair."

Sweeney just shakes his head.

"It's one of life's enduring mysteries."

Times researcher Natalie Watson contributed to this report. Contact Katie Mettler at kmettler@tampabay.com or (727) 893-8913. Follow @kemettler.