California's wildfire season is off to a brutal start. Through August, this year already ranks as the second most destructive in the state's history, with more than 1.6 million acres burned.

Sparked by lightning strikes and record heat, fires in Northern California have destroyed thousands of structures, wrecked air quality in the San Francisco Bay Area and carried smoke plumes as far away as Nebraska. With hot, dry weather likely to persist until November, the worst may be yet to come.

Looking farther ahead, the picture does not improve. As climate change worsens, wildfires are growing in number, scale and duration across the American West, overwhelming local firefighting capacities and putting property and lives in peril.

Since 2017, fires have consumed more than 20 million acres and caused at least $50 billion in economic losses. The U.S. needs a coherent national strategy to address the threat.

New resources, including extra staff, are essential if fires are to be fought more effectively. But prevention matters as well. Addressing climate change is vital, but other kinds of mitigation are possible too. These could do a lot for little or no net outlay — $1 spent on fire prevention is estimated to save $3 in costs — and deserve to be taken much more seriously.

The first task is bolstering the supply of trained firefighters. Firefighting teams are getting less help from volunteer prison inmates, thousands of whom typically work as firefighters, but whose numbers have been reduced to prevent the spread of COVID-19 in prisons.

To meet staffing needs, Western states like California should offer bonuses for seasonal firefighters and offer full-time employment for those who serve on the front lines. Former prisoners who've received firefighting training while incarcerated should be allowed to apply for full-time jobs after they serve their time, as proposed in a bill passed by California's Legislature.

A smarter approach would spend more on forest management, by conducting controlled burns and clearing vegetation during the offseason. Congress should pass legislation sponsored by California Sen. Kamala Harris to help vulnerable communities improve their defenses. Over the longer term, a corps of skilled workers could help state and local authorities strengthen fire resilience and restore healthy forest ecosystems.

At a time of trillion-dollar deficits, spending more on wildfire mitigation may seem like a tall order. It shouldn't be, for the simple reason that the costs of inaction are greater.

FROM AN EDITORIAL IN Bloomberg OPINION