Rain finally expected across Northern California. How much will it help with fires?
We need it. We need it really, really badly.
With wildfire after wildfire battering California since late summer, burning record acreage and killing at least 30 people in less than two months, weather experts have repeatedly said conditions conducive to critical fire risk probably won’t begin to subside until the first significant rainfall of autumn.
Rain might finally — and mercifully — be coming soon to Northern California. Some big questions remain: How much rain will we get? Where exactly will it fall? And will it be enough to end this year’s wildfire danger?
The National Weather Service in its latest forecast predicts a wet and cool storm track will sweep in from the northwest later this week and into the weekend. “Widespread precipitation” is possible across most of the north half of the state, the NWS Sacramento office said Sunday in a social media post.
As of Monday morning, there are still multiple major wildfire incidents burning across Northern California. These include the Glass Fire in Napa and Sonoma counties; the Zogg Fire west of Redding in Shasta County; the nearly 1 million-acre August Complex in and around Mendocino National Forest; and the North Complex near Plumas National Forest.
Let’s start with the good news: The latest NWS forecasts show at least a slight chance of rain beginning either Thursday night or Friday in all four of those areas. Forecasters also predict a slight chance of rain in Sacramento starting Friday and continuing into Saturday.
It’s still a bit too soon to estimate how much precipitation might fall in any of those regions, but the forecasts do say “rain,” not “showers,” at this point. The NWS also says there’s a possibility of wet snow at the “highest mountain peaks” in the Sierra Nevada range.
The system will also bring much cooler weather. Sacramento, which has had max temperatures in the low 90s since the start of October, is expected to cool down to 85 degrees Wednesday, 76 on Thursday and 72 by Friday, according to NWS forecasts.
Significant, widespread rain would hopefully douse the very dry vegetation that Cal Fire, the U.S. Forest Service and weather experts have described on a daily basis in incident reports as fodder for the recent wildfires, which have spread explosively during several gusty wind events since August.
Will this storm system be enough to do that?
That’s the not-so-good news. UCLA climate scientist Daniel Swain tweeted Sunday that this week’s weather system “is looking *unlikely* to be a fire season-ending rainfall event, unfortunately.”
It should become a bit clearer in the next few days how significant the storm will be, but as of early Monday, the NWS isn’t predicting significant rainfall to continue beyond Saturday.
“Uncertainty still high,” Swain reminded.
Five of the six largest wildfires in modern California history have already sparked since mid-August, chewing through thousands of square miles everywhere from the greater Bay Area to the Santa Cruz mountains to the Central Valley to the Sierra Nevada foothills to national forests like Plumas and Mendocino.
And for California in recent years, wildfire season hasn’t peaked until fall, the time of year when gusty winds — like those that have flared up the North Complex, Glass Fire, Zogg Fire and others — meet conditions that remain critically dry until there is sustained rainfall.
The last three years have reflected the fire danger that persists in the last three months of the year. October saw the start of the devastating 2017 Wine Country fires, as well as the Kincade Fire, California’s largest fire in 2019. The state’s deadliest wildfire ever, the Camp Fire, sparked in November. And the 2017 Thomas Fire started in December, scorching more than 280,000 acres in Southern California to become the largest fire in recorded state history at the time (it’s now No. 7 on that list).
This year, just a few days into October, the state has already smashed the all-time annual record for fire acreage. Over 4 million acres have burned in 2020, Cal Fire confirmed over the weekend. No calendar year between 1987 and 2019 even reached the 2 million-acre milestone.
Climate change and California wildfires
Wildfires have always been part of life in California. The past four years have brought some of the most destructive and deadliest wildfires in the state’s modern history.
Nearly 180 people have lost their lives since 2017. More than 41,000 structures have been destroyed and nearly 7 million acres have burned. That’s roughly the size of Massachusetts.
So far this year, 30 people have died, according to Cal Fire.
Meanwhile, this year’s August was the hottest on record in California. A rare series of lightning storms sparked a series of fires, including the August Complex that has burned nearly 1 million acres, making it by far the largest wildfire in California’s recorded history.
The 2017 wildfire season occurred during the second-hottest year on record in California and included a devastating string of fires in October that killed 44 people and destroyed nearly 9,000 buildings in Napa, Lake, Sonoma, Mendocino, Butte and Solano counties.
The following year was the most destructive and deadliest for wildfires in the state’s history. It included the Camp Fire, which destroyed the town of Paradise and killed 85 people, and the enormous Mendocino Complex.
This story was originally published October 5, 2020 at 7:29 AM with the headline "Rain finally expected across Northern California. How much will it help with fires?."
