Wildfires in the western U.S. have become a growing crisis. They’re lasting longer, burning hotter, and spreading into areas that rarely burned in the past.

But another danger is rising, beyond heatwaves and droughts. Lightning – sudden, fierce, and incredibly powerful – is becoming one of the biggest wildfire risks.

In the coming decades, scientists warn that lightning will become an increasingly dominant spark for wildfires, adding to the already mounting risks across the West.

Lightning is fueling more wildfires

Wildfires need a few things to get going: dry fuel, hot temperatures, low humidity, and a spark. Lightning is one of the most powerful natural igniters.

In the western U.S., lightning already causes more than two-thirds of the area burned by wildfires. And now, new research shows that number is going to rise sharply due to climate change.

Warmer air holds more moisture, which means more unstable weather patterns. Those patterns, in turn, set the stage for more lightning.

A recent study has revealed that virtually all of the western U.S. – 98 percent of the region – will have more days with a greater likelihood of lightning-ignited wildfires starting as early as the 2030s.

For regions already accustomed to such fires, such as Oregon, Idaho, and Montana, the risk is even greater. As early as 2060, those states may have as many as 12 additional lightning-filled days per summer.

A model to forecast lightning

Traditional climate models don’t really track lightning. That’s why a team of researchers led by Dmitri Kalashnikov built their own system to fill in the gaps.

“The first step was to project lightning,” said Kalashnikov, a research scientist at the University of California Merced. “The typical climate models don’t directly simulate lightning. It’s too small a process.”

The researchers applied machine learning to forecast where lightning would hit based on variables that we can quantify – such as temperature, humidity, and the level of moisture in the air.

The team merged those results with the Fire Weather Index (FWI), a mechanism that was developed back in 1968 to monitor how probable wildfire initiation and spread is from local weather.

The result is a forecast model tailored to the western U.S., designed to project conditions from 2030 to 2060 – decades earlier than most studies, which typically look only to the end of the century.

More lightning in the Northwest

The northwestern states of Idaho, Oregon, and Montana are projected to experience the greatest growth in lightning days. But strangely, they may not experience the most rapid expansion in wildfires.

Although lightning will grow, the conditions favoring fires (such as extreme heat or dryness) are not expected to worsen as quickly in the Northwest compared to other regions.

That doesn’t mean northwestern states are off the hook. Cloud-to-ground lightning, the kind that hits trees or grass directly, is still expected to rise significantly in those areas.

Less lightning, greater wildfire risk

In contrast, the Southwest – including Colorado, Wyoming, Arizona, and New Mexico – won’t see as much of a jump in lightning strikes. But the fire risk will still climb.

This is because even a small spark becomes a big threat when the land is extra dry, the heat is intense, and there’s little rain to cool things off.

The researchers found that these southern states are likely to experience the biggest increases in wildfires caused by lightning, despite the smaller bump in lightning activity. That’s because climate change is pushing up the number of fire-prone days overall.

Dry and wet lightning

Kalashnikov said the next steps could involve separating the kinds of lightning events. “You can’t help but wonder what the future will look like, especially if you dig in and you realize that there’s actually a lot that we don’t understand,” he said.

One key factor will be figuring out how to distinguish between “dry lightning” and “wet lightning.” Dry lightning happens without much rain, making it a fire hazard.

Wet lightning brings heavy rain, which can reduce fire risk but increase flood danger. Understanding that difference could help emergency services respond more precisely to fire threats.

Wildfire risks are rising fast

As climate patterns shift, the West isn’t just getting warmer and drier – it’s getting stormier in a dangerous way. Lightning is expected to spark more fires, and fires are expected to find more dry fuel waiting. It’s a feedback loop that could reshape fire seasons in the U.S.

This isn’t about something that might happen a hundred years from now. The changes are coming within the next few decades – some may already be happening.

And for the people living in high-risk areas, that means more heat, more smoke, and a greater need for preparation.

The full study was published in the journal Earth’s Future.

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