Good morning.

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Across Los Angeles, they sleep in tents, under tarps or out in the open air, and their numbers are growing. Last year the population of homeless people on the streets of Los Angeles increased 23 percent, and officials believe the numbers have continued to rise.

This week the city will start to find out just how much.

Starting Tuesday night in the San Fernando, Santa Clarita and San Gabriel Valleys, thousands of volunteers fanned out to neighborhoods to count the homeless, an annual three-day exercise that in recent years has confirmed an alarming crisis in Los Angeles County.

The count, along with demographic surveys, will help policymakers decide how to spend public money: $355 million per year raised by Los Angeles county from a special sales tax, and a $1.2 billion city bond issue to build housing for the homeless.

Once mostly associated with Skid Row, the vast tent encampment in downtown Los Angeles, the homeless are now spread out across the city, setting up tents under highway overpasses and moving into affluent neighborhoods like Bel-Air, where a wildfire that threatened the area’s mega-mansions was sparked last year by a cooking fire at a homeless encampment.