He said dry thunderstorms, which produce lightning but little rain, are expected for parts of the Rocky Mountain region, while the United States north-west has critical fire weather conditions that include strong winds and low relative humidity.
Three other firefighters perished while battling the devastating Carr Fire, which also killed four civilians and a utility worker and burned more than 1,500 structures.
So far, the Holy Fire has scorched more than 22,700 acres in the Cleveland National Forest.
Draper City Fire Department says "Our hearts are breaking as we announce the loss of one of Draper City's firefighters in the Mendocino Fire last night". The fire has now grown to over 349,000 acres, but the Ranch Fire - one half of the Mendocino Complex Fire - is up to 59 percent contained.
According to Cal Fire, the destructive ranch fire is still very active. In all, it has burned 295,970 acres, putting it on track to become the state's first single 300,000 acre fire.
More than 30,000 personnel, including firefighters from across the United States and almost 140 from Australia and New Zealand, were battling the blazes that have consumed more than 1.6m acres (648,000 hectares), according to the National Interagency Coordination Center. Two other firefighters had previously been injured fighting the fire.
The Carr Fire, which began nearly three weeks ago, has destroyed nearly 1,100 residences.
While it's not the largest burning in the state, the Holy Fire has raised concerns about effects on residential communities. Elsewhere, the Carr Fire has left a trail of destruction in Redding and the Ferguson Fire forced Yosemite National Park to evacuate portions of the park last month.
A Redding, California, family who fled the sprawling Carr Fire returned home to find something fishy had happened while they were away. "Now we can focus on the challenge of the Ranch Fire", he said.