Dry Lightning

Let’s talk lightning!
At least once a decade in California, a few hours of abundant and widespread ‘dry lightning’ (no rain) turn an average wildfire season into an exceptional one. Thousands of wildfires start, some in remote areas, and many will burn until fall rains come.

Unlike human-caused fires, which grow quickly when they ignite under windy conditions or start at the bottom of the hill and run to the top, lightning-ignited fires usually start on the upper 1/3 of the slope, and often back downhill slowly, with beneficial effects.

While hundreds of thousands or even millions of acres can burn after a major lightning bust, much of this acreage burns fire-adapted grass and brushlands, or underburns forest lands with ecologically-beneficial low or moderate severity.

Another reason lightning busts bring a large proportion of #goodfire? Lightning usually occurs during fast-moving mid-summer frontal passages. These events are often followed by weeks of stable weather, when heavy smoke from many fires lowers temperatures, raises humidities.

Once we have hundreds of fires going, it is impossible to extinguish them all, so fire managers have to triage. Fires farther from communities are often assigned a lower priority for scarce firefighting resources. Smoke often makes it difficult to use aircraft.

This triage is sometimes misinterpreted as ‘just letting fires burn’. But oftentimes, we truly just don’t have the resources to fight every fire. This isn’t always a bad thing. Lightning fires are truly doing the heavy lifting of ‘treating fuels’ across the backcountry.

Like it or not, in California, no amount of mechanical thinning or prescribed burning will begin to approach the acreage that is ‘treated’ by God during lightning busts. And why would we think we can do it better?

So why can’t we just let remote lightning fires burn? It’s kind of an impossible ask of our fire managers. Once all of this fire is on the ground, it is very likely some portion of it, somewhere, is going to be blown up into a real catastrophe once the strong offshore winds arrive in the fall. That’s not to say there aren’t places on the landscape where recent fire scars, natural barriers, or other attributes make it lower-risk to leave fires to burn; it’s just that our fire managers have had some searing experiences in recent years that have driven home the dangers even remote fires can pose to far-off communities.

Fire managers had to make a lot of tough calls in 2020. One decision was that portions of the North Complex in the Middle Fork Feather River were a lower priority than fires closer to communities like Susanville and Quincy. On 9/8/20, as part of the Labor Day firestorm that blew up huge fires all the way from Canada to California under strong east winds, the North Complex fire went from being a ‘good fire’ to an awful one, running 35 miles, burning tens of thousands of acres of forest land, destroying the communities of Feather Falls, Berry Creek and Brush Creek, and killing 16 people.

Smoke from the North Complex, 9/9/2020.

So what can we do? Acknowledge limits. We can’t put out every fire during a big bust. On the whole, our wildlands are better off after a big lightning bust. Some real bad fire happens too. But don’t blame the people who had to make impossible calls. They aren’t magicians.‘Mosaic burn’ in the Mendocino National Forest following the million-acre 2020 August Lightning Complex fires.