REDDING, Calif. — When Brian Rice fought wildfires in the 1990s, his time on the line was intense during the summer fire season, followed by months to recharge during the cooler winter. But fighting wildfires is no longer seasonal work in California.

“There used to be a rhythm to this, and you could at least count on that rhythm,” he said. “It’s a year-round cycle now.”

Since 2012, according to state emergency management officials, there has not been a month without a wildfire burning — a stark contrast to previous decades, when fire officials saw the fall and winter as a time to plan and regroup. The recent historic drought and rising temperatures have heightened an already serious risk for widespread fires in the state.

Just this month, there have been three firefighters killed on the front lines, including two who died during a rapidly expanding wildfire in Northern California in the last two days. Dry conditions and triple-digit temperatures added fuel to that fast-moving blaze, known as the Carr Fire, as it marched eastward, swept over the Sacramento River and pushed into the outskirts of Redding, the largest city in the region. It continued to grow on Friday, burning dozens of buildings and prompting emergency officials to issue an urgent plea for people in parts of Redding and the surrounding areas to evacuate immediately.