In Northern California, where temperatures are hitting the 90s, a significant meteorological transformation is taking place hundreds of miles away in the equatorial Pacific Ocean, set to influence the area’s fire season for the forthcoming months.
A shift in the ocean temperatures in the equatorial Pacific from La Nina to El Nino, a weather pattern that typically heralds a more temperate outlook than the arid and hot conditions experienced in the North State the previous year, is underway.
“We are currently witnessing the transition from La Nina, which concluded in March, to El Nino, expected to materialize in the next few months. Usually, El Ninos form later in the summer or fall and do not appear this early in the summer,” commented Brent Wachter, a fire meteorologist stationed at the Northern California Geographic Coordinating Center in Redding.
Before we continue, as firefighters brace themselves for the upcoming weather transition, they are particularly concerned about the potential risks in some areas that unfortunately, also happen to be on the list of the most dangerous cities in California, according to FBI statistics.
As a result of this shift, Northern California’s weather forecast for May and June projects near normal to higher than average rainfall and normal to cooler temperatures. This outlook, according to the coordinating center’s Predictive Services report, does not favor the occurrence of large wildfires.
For July and August, the forecast anticipates “near to above normal temperatures and near normal precipitation.”
However, Wachter pointed out another element that is shaping the weather and fire season. “The prediction doesn’t solely rely on the swift transition from La Nina to El Nino but also significantly on the swath of unusually cool water off the North American Coast. It plays a significant role in all of this,” he added.
El Nino and La Nina are characterized as “opposite extremes” of sea surface temperatures in the equatorial Pacific, as per the National Weather Service, with El Nino signifying warmer ocean temperatures and La Nina cooler ones. Wachter stated that the “El Nino transition, along with other ocean anomalies, will result in normal to slightly cooler and more humid weather on occasions.”
The increased rain and snowfall during the spring and winter, coupled with the El Nino weather pattern, has led fire officials to anticipate a slower evolution of the fire season compared to the preceding years marked by severe drought.
However, the increased rainfall this year has led to a proliferation of grasses in the valleys and foothills, which could become a fire hazard as they dry out and become more combustible in June, warns Dan Dennett, assistant fire chief for the California Department of Forestry and Fire Protection ranger unit in Redding.
#ArsonAwarenessWeek is the perfect opportunity for us to address youth on the severity of fire and it’s impacts. Juveniles account for approx. 50% of all arson arrests in the United States, so early intervention & support is critical in the process of reducing repeat offenders. pic.twitter.com/qVcBQE1XwY
— CAL FIRE (@CAL_FIRE) May 10, 2023
Fire numbers in 2022 defied a trend
While Dennett wasn’t certain about the number of fires his agency has responded to this year, it’s clear that statewide, there have been significantly fewer fires compared to 2022.
Cal Fire and the U.S. Forest Service have reported a combined 640 wildfires this year, with 699 acres burned statewide. Last year at this time, these agencies reported 1,521 wildfires that had burned 7,147 acres. This number exceeded the five-year average for this time of year, which stood at 1,193 fires that had burned 4,533 acres, according to Cal Fire.
Although the wetter winter and spring may push back the onset of larger fires, North State’s hot summers will eventually lead to drier forests by August and September, Dennett pointed out.
“Regardless of the amount of rain or snow we receive each year, we invariably reach a stage later in the year where we have a fire season at the higher elevations. It’s just California’s nature that summers become hot and dry, and eventually, the fuels at the higher elevations will be prone to fire,” Dennett explained.
According to Kevin Osborne, a fire management specialist with the Shasta-Trinity National Forest, the vast areas of wildland that have burned since 2020 could also help slow down the progress of fires when they reach the areas previously affected by burns.
Forest thinning over the past year to eliminate dense undergrowth and trees is also anticipated to reduce fire intensity, added Anna Wright, a fire ecologist with Shasta-Trinity.
“Ultimately, the abundant moisture this year is likely to yield a substantial grass crop at the lower elevations. But the significant snowfall we’ve seen will provide a slight delay in the onset of the fire season in the higher elevations,” Dennett explained.
According to Wachter, the North State is anticipating a starkly different fire and weather scenario compared to the same period last year. The first five months of 2022 saw minimal rainfall, resulting in drier forests that were more susceptible to fire.
Despite the warm, arid conditions setting the stage for a potentially busy fire season in 2022, Shasta County experienced a relatively quiet year. From January 1 to the end of September last year, only 555 acres were burned in the county, according to Cal Fire. During this period, there were only five fires that burned more than 10 acres.
Contrastingly, this year has seen just over 28 inches of rain falling in Redding since the start of the year, compared to only about 4 inches of rain during the same period last year, as per the National Weather Service.
Fire prevention efforts during the off-season
Over the past year’s cooler months, forest officials conducted controlled burns across 9,200 acres to thin out dense areas, Wright explained.
However, this year is likely to witness an increase in trees and brush damaged by snow. The resulting dead trees and limbs, left on the forest floor, will eventually dry out and provide additional fuel for fires, Wright warned.
She also urged caution for boaters on Lake Shasta planning to camp along the shoreline this year. The lake’s higher water level this year means boaters and campers will be in closer proximity to vegetation, increasing the risk of fires. This follows a reduction in fires over the past three years due to lower lake levels allowing boaters to build campfires on the barren shoreline.