Just how bad will California’s summer wildfire season be?

The consensus among experts is that the next few months will see above-average fire activity as has been the case in recent years amid a changing climate marked by hotter temperatures and longer dry periods. Nearly all of California is in a severe or extreme drought, according to the U.S. Drought Monitor.

“We do have the ingredients for an active, above-normal fire year, with the snowpack being below average,” said Brent Wachter, a fire meteorologist at the U.S. Forest Service’s Geographic Coordination Center in Redding, Calif. “We also have an above-normal grass crop. That’s a big driver.”

This year’s grass crop got a healthy boost when a string of weak storms delivered light rain to Northern California in May and June. While the systems may have prevented wildfire conditions from advancing rapidly in Northern California in June, they didn’t provide enough precipitation to put a dent in the state’s drought. Plus, they helped grasses grow more prolifically. Those grasses will dry out quickly in summer when the state typically receives no or very little rain and heat events are common, creating fuel for wildfires.

This year’s meager snowpack is only exacerbating the dire situation. In an ideal year, a robust snowpack is spread across the Sierra Nevada by spring, and it melts through summer with the runoff feeding the landscape. When the ground and vegetation are moist, fires don’t spread quite as rapidly. This year, while the snowpack got an early start with a historic October storm and a wet December, January through March were abnormally dry, resulting in a well-below-average snowpack. Going into summer, little snow remains in the Sierra Nevada range this year, with the northern section at 16% of normal for this date and the central and southern at 0%, according to the California Department of Water Resources.

Without a slow trickle of snowmelt through summer, trees and plants dry out more quickly and some will die. Trees that don’t get enough water become stressed and more prone to bark beetle attacks that kill trees. “Since 2010, an estimated 129 million trees have died in California’s national forests due to conditions caused by climate change, unprecedented drought, bark beetle infestation and high tree densities,” the U.S. Forest Service said.

There may be a bit of good news: While peak fire season is bound to be more severe than average, there’s a chance it might not be as bad as last year’s near-record or the 2020 season, a study by the National Center for Atmospheric Research said. The scientists estimated the number of acres that are likely to burn in the West by analyzing precipitation, temperatures, drought and other climate conditions in the winter and spring.

“What our research shows is that the climate of the preceding winter and spring can explain over 50% of the year-to-year variability and overall trend in summer fire activity,” Ronnie Abolafia-Rosenzweig, the lead author of the study and a researcher at the center, said in a statement. “This gives us the ability to predict fire activity before the summer fire season begins.”

The researchers predicted that that fires this summer will burn 1.9 to 5.3 million acres in the West, with 3.8 million acres being the most likely total. Although well short of the record 8.7 million acres burned in 2020, this would represent the 8th-largest burned area since 1984, a continuation of the long-term trend of more widespread conflagrations, the study said.

Of the study, Wachter said his “professional guess” is this upcoming season will be severe — but not as bad as in 2020 when a dry lightning storm in August sparked fires throughout California or last year when the Dixie Fire grew to be 963,309 acres, becoming the second-largest wildfire in state history.

Wachter said long-term weather forecasts suggests heat waves this summer may be less intense than in recent years, and this could help lower wildfire risk.

“This summer, the heat wave events aren’t expected to be as prolific and as long as duration in previous years,” he said. “We’ve seen several excessive heat warnings issued for 4 to 5 years in a row. I would expect they would be a little more limited this year.”

This point is reinforced in the most recent wildland fire seasonal outlook for June through September from the National Interagency Fire Center in Boise. “Drought conditions are expected to intensify some during the summer, but likely not as dramatic compared to the previous two years due to less potential for extended hot periods,” according to the outlook created by experts from more than a half dozen government agencies, including the Bureau of Land Management and the U.S. Forest Service. “Regardless, dead fuel moisture will spend ample time at unusually dry and critically dry levels, especially away from the coast. Live fuels will continue to become more flammable starting with the lower elevations and transitioning upwards in elevation from June into July, with coincident critically dry dead and live fuels expected to increase during this period then continue into August and September.”

Wachter said that while certain factors impacting the fire season are easy to predict, what he calls “acute weather” events, such as dry lightning storms that spark fires and offshore winds that fan flames, are much harder to pin down.

“Any kind of lightning can be problematic, especially if it’s of the dry variety, especially if it’s a mix of wet and dry,” he said.