In post-disaster reactions, formal benefit societies of our time often lend aid to others outside their immediate membership, while "ad hoc" benefit associations form among neighbors or refugees, generally lasting only as long as the emergency exists. "Ad hoc" mutual aid associations have been seen organized among strangers facing shared challenges in such disparate settings as the Woodstock Music and Arts Festival in New York in 1969, during the Beijing Tiananmen square protests of 1989, for neighborhood defense during the Los Angeles Riots of 1992, and work of the organization Common Ground Collective which formed in New Orleans after Hurricane Katrina in 2005. The Rainbow Family organizes gatherings in National Forests of the United States each year around age old models of "ad hoc" mutual aid.