“There’s visual similarities in the disorder and chaos and smoke and fire and all that,” said Robert Spangle, who lives in Malibu and served in the Marine Corps, with two deployments to Afghanistan.

Mr. Spangle is now a photographer, and has worked in Iraq, too. Over the last several days, he has put down his camera and picked up his radio, working to spot flames in the area of the Woolsey Fire and then help others to put them out before they spread.

The emotions that can make war so addictive — not just the adrenaline and excitement of living close to danger, but the humanity that comes forth — are bound up in these disasters in California, emotions that Mr. Spangle described as a “feeling of brotherhood and shared kinship.”

That feeling was palpable in Baghdad or Mosul or Kobani, Syria, where I have reported from. And it’s been palpable in Malibu — in normal times, a place of wealth and celebrity and sunshine, but amid a calamity, not much different in some ways from any other suffering corner of the globe.

“There’s that sort of communal bond that really comes out in adverse conditions,” Mr. Spangle said.

In Iraq, he said, he saw neighbors carrying the injured down the street, and in Malibu he has seen similar moments of people helping one another. “The neighborhoods here in Malibu are really tight-knit,” said Mr. Spangle, whose mother lost her house in the fire.