Theories abound about the reasons for booming homelessness downtown but no one can explain exactly why it’s booming.
Since January alone, a business group’s monthly census has shown a 68 percent spike in street homelessness downtown. The count peaked at nearly 1,400 in August and has since hovered around 1,130. More tents line city blocks  and more homeless people cluster near freeway on-ramps, businesses and homeless services.
Some local leaders have said Proposition 47 , a state ballot initiative that downgraded some felonies to misdemeanors in an effort to reduce the state prison population, is a significant culprit. Others have speculated about the impact of high rents, an influx of homeless people from other areas and even the way the homeless population is counted.
Homeless service providers and data gurus aren’t so sure what’s driving the massive uptick.
“We need a really comprehensive, in-depth look at what’s going on,” said Amy Gonyeau, chief operating officer of nonprofit Alpha Project.
Here’s what we know and don’t know about street homelessness downtown.
Two groups track homelessness downtown.
The best-known annual census  is conducted by the Regional Task Force on the Homeless, which sends volunteers out countywide to count those living on the street and in shelters between 4 a.m. and 7 a.m. one morning in late January.
This year’s point-in-time count revealed an 8 percent drop in overall homelessness citywide but a 21 percent increase in street homelessness in downtown census tracts. The group counted more than 1,000 people on downtown streets.
A monthly survey  organized by the Downtown San Diego Partnership, a business group, has gotten more attention this year as the homeless population booms.
Homeless outreach workers with the Downtown Partnership fan out across 275 city blocks between midnight and 5 a.m. the last Thursday of the month.
Here are the totals they’ve recorded since they started taking counts in 2012.
The Tent Factor
As street homelessness increases, so too has the number of homeless San Diegans with tents  – and that affects the numbers.
Since 2012, the Downtown Partnership has assumed two people are sleeping in each tent outreach workers come across. But the group doesn’t report the number of tents they see, making it difficult to conclude how much tents could be increasing the monthly count.
Alonso Vivas, who supervises the Downtown Partnership’s homelessness efforts, admits the approach isn’t foolproof. He said one could argue it may also undercount the population.
The Downtown Partnership’s opted to stick with that method because it allows them to better compare data over time, Vivas said. “We want to stay consistent.”
This January, the Regional Task Force counted more than 200 tents downtown, a 52 percent increase from last year. Then they assumed 1.72 people were sleeping in each one which translates into about a third of the more than 1,000 homeless counted on downtown streets this January.
San Diego’s Homeless Hub
Downtown San Diego has long been the regional headquarters for homeless services . It’s a place where homeless folks can get a meal, a shower or a shelter bed – resources that aren’t as plentiful elsewhere.
Many have told me they came downtown or have stayed there for that reason, even if they aren’t looking for shelter.
“All the resources are here,” said Thomas Easthope, 51, who I met last week near Fault Line Park  in East Village.
Easthope and others stress that life downtown isn’t easy. They’re frustrated with police enforcement , weekly sidewalk clean-ups  and an increasing population  in a time of much construction and development that’s forcing homeless people into smaller areas.
“They’re jamming us in one place,” Easthope said.
Still, the draw endures – for now.
Dolores Diaz, who leads the Regional Task Force on the Homeless, said the data her group’s collected seems to show homeless San Diegans are migrating within the region, especially to downtown census tracts.
That might explain one seemingly contradictory takeaway from this year’s countywide count. Street homelessness actually fell nearly 1 percent citywide from 2015 to 2016 but rose downtown.
The Prop. 47 Effect
In Nov. 2014, California voters approved Prop. 47, reducing certain felonies to misdemeanors. It gave authorities less power to crack down on repeat drug and property crime offenders  and to persuade them to enroll in treatment programs. It also led to the release of tens of thousands  statewide from prisons and probation terms.
In the two years since, the downtown homeless population has more than doubled – and some local officials have been quick to note the circumstances.
City Councilwoman Lorie Zapf and a chief deputy city attorney wearied over the challenges the initiative has wrought at a recent town hall meeting.
“It is clear to everyone, even though the statistics are lagging, that since the implementation of Prop. 47, it correlates with the increase in these aggressive transients, with these thefts, with the crazy amount of drug use that we’re seeing out on the streets, like right out in the open, right now,” said Zapf, who is most focused on homelessness in the beach communities she represents.
Before Prop. 47, Zapf said, drug offenders facing greater punishment had an incentive to enter rehabilitation programs that might help them move past addiction. Now, she argued, they’re increasingly ending up on the street without the help they need.
Meanwhile, homeless outreach workers and other downtown groups have noted increased drug and gang activity among the homeless population, especially in East Village. The Downtown San Diego Partnership has said workers who clean and watch over downtown streets as part of the group’s Clean and Safe Program are increasingly being assaulted on the job.
Data recently released  by SANDAG, the regional planning agency, underlines the vulnerability of drug offenders and their risk of homelessness – and how that might be changing post-Prop. 47.
In 2013, 56 percent of drug arrestees interviewed by the agency as part of a years-long analysis reported they’d ever been homeless. Of those, 28 percent said they were homeless when they were arrested.
Two years later, with Prop. 47 in effect, 62 percent of arrestees reported they’d ever been homeless and 40 percent of those said they were currently homeless.
Yet many nonprofit leaders and other officials are hesitant to publicly claim cause and effect. They aren’t specifically tracking who’s moving onto downtown streets or monitoring folks who might otherwise be jailed or on probation.
What they do know is that 14 percent of unsheltered homeless folks surveyed by the task force reported they were on probation or parole and 62 percent countywide reported they’d served time in jail, prison or juvenile hall. Of those, 85 percent said they’d been released within the last five years.
Division Chief Gonzalo Mendez of the San Diego County Probation Department is familiar with those numbers and anecdotes about Prop. 47. He regularly attends monthly meetings focused on coordinating homeless-serving efforts countywide and is concerned drug offenders once easier to help push into treatment aren’t getting that treatment.
But he thinks more research is needed to draw a direct correlation between Prop. 47 and rising street homelessness.
“I don’t know what the answer is,” Mendez said. “I know we have 2,700 less offenders (on probation) but we can’t say all those people are homeless or don’t have a place to live.”
Diaz of the Regional Task Force also argued the data the homeless-serving community has now isn’t enough to conclude that Prop. 47 is driving increases in street homelessness downtown.
“I don’t think we should say that Prop. 47 has anything to do with it,” Diaz said.
Who’s Coming In
San Diego’s mild climate and stories about homeless folks being bused  in feed a common notion that much of the region’s homeless population could be coming from elsewhere. That theory’s  also been circulated as street homelessness grows downtown.
But the most reliable data indicates more than two-thirds of homeless San Diegans ended up on the streets while living in San Diego rather than move here after they became homeless.
Downtown San Diego Partnership CEO Kris Michell has often said many homeless folks who settle downtown aren’t from San Diego and that this may make it different than other parts of the county.
At a town hall  last month, Michell said about 70 percent of homeless people her workers had surveyed reported they came from outside California.
But that statistic is based on reports from participants in the organization’s family reunification program , which helps homeless people reconnect with family members.
“We don’t extrapolate that to apply to the entire population of homeless people downtown,” spokeswoman Angela Wells said.
This detail matters. Someone who is seeking help to reunite with family members is more likely to have family outside California or at least San Diego County.
Other data, though imperfect, tells a different story.
This year, about 70 percent of unsheltered homeless folks countywide interviewed by the Regional Task Force said they’d become homeless in San Diego . About a quarter reported becoming homeless elsewhere.
A downtown-focused effort  in 2014 drew similar conclusions. Two-thirds of the more than 2,200 homeless folks surveyed downtown reported they lived in San Diego County before they became homeless and nearly 70 percent said they hailed from Southern California. And again, just under a quarter reported living elsewhere before they ended up on the street.
Raul Palomino, executive director of homeless-serving Presbyterian Urban Ministries in Sherman Heights, said he believes the trend has shifted recently.
Palomino, whose organization that helps homeless folks secure IDs and birth certificates necessary for long-term aid, said he’s noticed an uptick in clients from outside San Diego. He acknowledged many of those clients come via a more recent partnership with a private prisons operator that uses his service to prepare clients to move out of halfway houses.
“Lately, it’s been more people who are brand new to San Diego,” he said.
Affordable Housing Shortage
San Diego’s rising rents and low vacancy rates  are especially daunting for would-be tenants with past evictions, low credit scores and limited cash.
And there are now fewer than half as many units in downtown residential hotels that once served as a last-ditch option folks who might otherwise be homeless. Many have shuttered or started charging more .
A Housing Commission survey  last fall concluded the city was home to just 3,872 single-room occupancy units – fewer than half of the citywide stock reported in 2003.
Homeless advocates are adamant the loss of those units, many of which were downtown, is contributing to the downtown homelessness crisis.
“The SROs were the safety net,” said Jim Lovell, who leads the downtown Third Avenue Charitable Organization.
Lovell, whose organization serves meals and connects homeless clients to other services, said the $750 to $800 monthly SRO rates he’s seen recently are out of reach for many seniors and people with disabilities.
Many SROs that remain aren’t inviting, either.
Lovell said one client who’d spent years on the street found work and nabbed an SRO for $650 a month only to be preyed upon by bed bugs. That lasted a couple months.
Now he’s back on the street.
Lovell suspects there are many stories like that – and even more stories of homeless folks who might have avoided that scenario years ago.
“People who typically, in years gone by, would just be not outside, just barely not outside, are back outside,” Lovell said.