Investigators say more than half - 161 in the first 14 days of the year - were connected to homeless activity.
Crews are now proactively tackling these fires and teaming up with city leaders to reduce.
The crew at Fresno Fire's station 3 is doing pre-fire planning at one of hundreds of vacant homes throughout the city.
Fresno Fire PIO Shane Brown says one building at Plumas and Whitesbridge has caught fire at least six times, so the idea of the day's work is to prepare not for 'if' but 'when' it burns next.
Just four days earlier, a firefighter was injured by a wall collapse of a vacant house on 5th and Woodward. Though he was cleared to return to work after being treated, the hazards could be deadly.
"It's a sobering reminder for all of us that when we enter these buildings that have been neglected for so long, we don't know what we're going to encounter," says Brown.
Brown would know. He was sidelined for seven months because of a similar fire.
"I actually tore my ACL at a vacant structure fire. To my knowledge it was the 4th time that building had burned," says Brown.
Brown says the city's new administration is coming up with new ways to address the issue.
"I feel like they're very invested in trying to identify the best way to handle this in the most humane way possible that's actually going to make a difference," says Brown.
Mayor Jerry Dyer says his "housing the homeless" initiative will kick off as soon as next week.
"When you look at last year in our city, 618 fires were caused by the homeless population on our freeways alone," he says.
"We have an opportune time with Project Homekey's number of hotels that we've been able to purchase with the housing authority and the City of Fresno. Those are going to be opening up and we'll place homeless individuals in that housing environment with services," he adds.
The idea is to stop people from entering vacant buildings.
You can do your part as well. These homes may be in your neighborhood, maybe even next door, so report them by using the FresGO app.