Up to 20,000 "members" of the Rainbow Family of Living Light will gather in the Green Mountain National Forest in the coming weeks. 

An unofficial website describes the Rainbow Family as the "largest non-organization of non-members in the world." Since 1972, the loose-knit, peace-loving group has descended on different national forests for annual gatherings that occur around July 4 and are open to all.

The group promotes intentional communities and nonviolence but its large get-togethers haven't always been conflict-free. There have been violent incidents and controversies over the environmental impact on the parkland where members camp. 

This year, according to the U.S. Forest Service, the Rainbow Family has chosen the tiny Rutland County town of Mount Tabor.

The Forest Service issued a press release Monday morning notifying Vermonters about the incoming crowds, which are expected to arrive in the upcoming weeks. 

In preparation, a National Incident Management Team has arrived in town and "is working with various local agencies to address public health and safety, while managing and minimizing adverse impacts to natural resources."

"Local businesses can expect to see large numbers of Rainbow Family participants visiting stores, buying food and supplies along routes to the gathering site," the release says. "Areas are expected to be very congested during that time."

If previous gatherings are any indications, some nudity, drugs, drum circles, dancing and heady discussions can be expected as well.