Paiz was driving his water tender east down Oakville Grade at 6:50 a.m. Monday when the vehicle went off the roadway and rolled over onto its top, according to Cal Fire.
News of his death spread hours later to Coachella Valley, where his mother, brother and sister live.
Paiz's mother told the Desert Sun she received a call that afternoon.
"He says, 'I'm from the Napa Sheriff's Department, there's been an accident,' and (I) remember just dropping the phone," Judi Paiz said.
The California Highway Patrol, which is investigating the crash, says the truck had no water in it and Paiz was heading down to the valley to get it refilled. CHP investigators spent Monday mapping evidence and roadway markings. On Wednesday, the water tender was stored for evidence and investigators planned to inspect it by the end of the week, according to CHP Sgt. Rob Nacke.
Paiz was employed by Red Bluff-based Tehama Transport. Cal Fire has hired the firm 56 times in the last four years, according to documents obtained by KQED.
The company, like scores of other contractors, has provided water tenders and bulldozers to firefighting efforts. Firms that contract with Cal Fire for heavy equipment are required to provide copies of their current workers' compensation insurance policies for their employees.
But Tehama Transport did not have to abide by that requirement because it registered as an "owner/operator." Under that classification, the company was saying that Paiz either had ownership in the company or was a relative of someone who did.
Without that coverage, Paiz's family, his wife and teenage daughter, might lose out on hundreds of thousands of dollars in benefits.
Paiz lived most of the year in Missouri but worked several months out of the year in other parts of the country doing wildland firefighting, according to two of his most recent employers.
Because of the confusion over his relationship with the company, Cal Fire has referred questions over Paiz's coverage to state workplace regulators.
That has prompted the California Department of Industrial Relations and the state Labor Commissioner's office to launch an investigation into Tehama Transport, DIR spokesman Peter Melton said in an email Friday.
Company representatives have not returned requests for comment, but have offered support through an online fundraising effort.
"On behalf of Tehama Transport, we are deeply heart broken ..." wrote Heather Ascherin Morway on the memorial fund site.
"We would like to send our deepest condolences to his family. This is a tragic accident and our thoughts and prayers are with Garrett's family at this time. We will continue working with the local authorities to bring peace and closure to his family. This is a very difficult time for all of us out there that fight fires when we lose one of our own," Morway wrote.
That grief extends to communities in Missouri, where Paiz's love for firefighting was well known.
"That was his passion. That was his dream," said Brandon Barrett, the chief of the Noel Fire Department, where Paiz was employed in the last year.
"It's heartbreaking, it's a tremendous loss," Barrett said in an interview Wednesday, adding that Paiz was planning on returning to work in Missouri in November.
Several members of the department plan to travel to California next week to attend Paiz's funeral, according to Barrett.
Barrett and Gary Banta, the chief of the Fire Department in Dade County, Missouri, where Paiz worked for several years before Noel, said he made it clear to them that several months out of the year he would work as a wildland firefighter in other parts of the country.
"He always had a smile on his face ... willing to do anything to help anybody out," said Banta.