"The true cost won't be known for months or years afterward," he said.
He added: "What the state is looking for is the highest level of federal support, which requires the highest bars be cleared. But we feel our case for those requirements has been met."
According to Ferguson, such aid could easily reach into the hundreds of millions of dollars.
The state is also asking for aid for San Diego County's Valley Fire, Mendocino County's Oak fire and Siskiyou County's Slater fire.
Newsom formally submitted a letter to the White House and FEMA on Sept. 28 asking for such a declaration and citing the fact that five of the six largest fires in California's recorded history have taken place this year.
The biggest is the August Complex fire, which began Aug. 16 and as of Oct. 15 had burned just over 1 million acres through seven Northern California counties and was 77% contained.
Newsom also said funds would go toward helping rebuild public infrastructure, miles of roads, parks, signs and fire shelters.
"Many of the counties impacted by these wildfires are still recovering from previous devastating wildfires, storms and the effects of the COVID-19 pandemic," Newsom wrote.
He added, "Californians are exhausted."
The governor also noted the cash-strapped nature of the state, which is projecting a pandemic-induced $54.3 billion deficit this fiscal year.
In February, the federal government agreed to pay back California more than $170 million for repair to the Oroville Dam spillway. Overall, the government kicked in $562.5 million for the project.
California previously successfully applied for a declaration from the federal government for two fires caused by lightning, including the Complex fire, in August.
Newsom will also probably ask for another disaster declaration, Ferguson said, for the Glass fire in Sonoma County and the Zogg fire in Shasta County. The Zogg fire was extinguished on Tuesday, while the Glass fire is 97% contained.
Visit the Los Angeles Times at www.latimes.com(c)2020 Los Angeles Times, Distributed by Tribune Content Agency, LLC.