Seattle has grappled with tent cities for decades. Under a 2002 Consent Decree, a group known as Share/Wheel was granted permission to run an encampment within city limits under certain conditions - including a maximum three months at any one site.
The roving camps are usually hosted by church groups. In 2009, a Washington State court found the city of Woodinville violated a church's constitutional rights when city officials declined to process the church's application to host a tent city, bolstering religious group's right to host the compounds.
Currently, Seattle is home to "self-managed" encampments of Tent City 3 and Nickelsville. Tent City 4 is a roving encampment in the suburb of Kirkland, and there are unsanctioned groups of tents in greenbelts and other pockets of the city.
Nickelsville - named after former Seattle mayor Greg Nickels, who came under fire for what some viewed as harsh policies on homelessness - is set up at a former fire station, with some residents inside and others in tents.
Nickelsville organizers want the city to set up a permanent encampment on city-owned land - an option the city is weighing. An environmental report on a potential site is expected in February; if the site passes muster, the proposal would require funding and zoning approval.
Preliminary estimates have pegged the cost of the city-sanctioned encampment at less than $1-million a year.
Some Vancouver housing activists have suggested erecting tents or slightly sturdier structures on city property to provide shelter for people sleeping on the street, but officials are not considering that possibility.
Health and safety concerns - for prospective residents and staff - make tent encampments a non-starter, Vancouver Councillor Kerry Jang said. "It's just not good public health," he said.
Co-ordinated efforts by the city and province, including emergency cold-weather shelters that are open 24 hours a day and accept pets and shopping carts, have helped reduce street homelessness, he added.
Seattle's Ten-Year Plan to End Homelessness, introduced in 2005, says that it "neither promotes nor disapproves of tent cities. Rather, it acknowledges that tent cities are an emergency response to the greater problem of homelessness in King County, and a safer alternative to life on the streets. Once safe, decent and affordable housing is available for all our citizens, tent cities will not be necessary."