Washington Governor Bob Ferguson said it was a “nightmare situation”, adding: “This is likely the worst natural disaster in Spokane history.”
The city’s mayor Lisa Brown said there was still “the potential for lives to be lost” and that it was too early to say when people might be able to return home.
No deaths or injuries have been confirmed.
The destruction, however, has left local residents in shock and despair.
“I shouldn’t have been back here, but I had to see my house,” Ken Anderson told NBC News, standing near the skeletal remains of his home.
His wife, Lisa, said: “It seems like it’s a nightmare that we are just gonna wake up from and it’s all gonna be okay, but I don’t think it’s going to be okay.”
Online fundraisers for those affected by the wildfires tell similar stories.
Jane Biernat, who is six-months pregnant with her second child, safely escaped the wildfire but lost “everything” when her apartment in Spokane burned down, according to a verified GoFundMe page set up by her family.
“In just a few minutes, their home, clothes, furniture, baby’s belongings, and all their cherished memories were gone,” the account said.
“Without renters insurance, they are now faced with the daunting task of starting over from nothing.”
Authorities are trying to make contact with 14 people they have been unable to reach by mobile phone but are not yet considered missing.
Sheriff John Nowels said it was likely many of them did get evacuated but had lost signal or had depleted phone batteries.
The three fires in the city – Old Trails, Fairview and Autumn Lane – are among a total of 16 wildfires in Washington state, according to the state’s department of natural resources.
Firefighters have made progress against two of them but while lighter winds and cooler temperatures have been forecast on Tuesday, temperatures are feared to be rising again later this week.
Farinacci, who was arrested over the Old Trails fire, is being held on a charge of arson in the first degree and held on a $1m (£744,150) bond.
Nowels said the Spokane resident had a previous manslaughter conviction.
