SAN FRANCISCO (KGO) -- It's that time of year again in California. The rain -- or at least what there was of it -- has stopped. The hills have gone from greenish to yellow to brown. The snowpack in the Sierra is melting and the winds are kicking up.
And we wait.
We wait to see what will come of California's "fire season," which has grown longer and more devastating in recent years.
How bad will it be this year in 2021? I asked ABC7 News meteorologist Drew Tuma. His answer comes in two parts: what we know and what we can't predict.
There are a few key puzzle pieces in place setting us up for a potentially devastating fire season in California, the first of which is the drought.
"Right now, 40% of the state is exceptional drought, which is the worst category you can be in," said Tuma. "But if you compare that to our drought over the last decade, at the height of it in 2014, it was almost 60%."
The worst drought conditions are centered in and around the Bay Area, he said. With our driest months still ahead of us, it's expected that more of California will be in the "exceptional drought" category.
The drought is a problem because all of our vegetation is dry and therefore highly flammable.
Already this year, CAL FIRE is reporting more than 16,000 acres burned. Around this time last year, it was 3,600.
With that in mind, the agency is predicting a harsher and longer fire season. In parts of the Sierra, the fire season is about 75 days longer than it used to be, CAL FIRE said.
"Climate change is considered a key driver of this trend," CAL FIRE writes. "Warmer spring and summer temperatures, reduced snowpack, and earlier spring snowmelt create longer and more intense dry seasons that increase moisture stress on vegetation and make forests more susceptible to severe wildfire."
"The predictable elements all point to a really extreme fire season," said Tuma. "It's just that trigger that we can't predict until the near-term."
Here's what remains to be seen between now and October: the number and strength of heat waves, the ferocity of Diablo winds and the new wildcard possibility of lightning storms.
First off, heat waves only make things worse by further drying out the landscape.
"In the summertime, we definitely look at heat a lot," explained Tuma. "The first half of June looks lower than average temperature-wise, and that's something we're really looking for."
So far so good when it comes to heat waves, it seems. But it's even harder to predict winds more than a week out.
As Californians know by now, winds don't just fan flames of existing fires -- they can start fires, too, by knocking over power poles.
Not all wind is bad, however. Onshore winds, which come from the Pacific Ocean onto land, help keep humidity levels high -- great news for fire danger. It's in September and October when things switch, and we see offshore winds, that fire danger shoots up.
"It's a dry wind and a dangerous wind. That's not the wind you want to see."
They're called Diablo winds because they originate over Mt. Diablo and blow out to the water. (Its translation to the word "devil" in English is purely coincidental and apt.) We don't see strong Diablo winds every fall, though, so it's another unknown factor at this point.
Finally, the biggest X factor of all: lightning, the cause of the CZU, LNU and SCU complex fires that devastated Northern California in August 2020.
Tuma remembered watching the radar showing lightning strike after lightning strike.
"That's just something that's truly once in a decade, if not once in almost a lifetime, that we see that much lightning in such a short amount of time."
Longtime Bay Area residents know that we don't see summer storms here practically ever. Betting odds would say we probably won't see it this year.
"But it has happened once," Tuma pointed out. "It could happen again."
Tuma, unfortunately, cannot control the weather. He doesn't know how many fires there will be this year nor how damaging they will be. But we have learned from years of traumatic experience that we should prepare for the worst.
"If you know that you live in an area that is prone to the threat of wildfires, try and build that defensible space around your home or property," Tuma said. "If you can build that barrier between your house and vegetation, that can really save your property."
One (and perhaps the only?) silver lining of the years of massive fires we've been seeing in California: those burns scars protect us in the near-term.
"If you live in an area that already burned last year, there's nothing to catch fire."
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