Fires are raging in Southern California and it’s only May. What’s going on?
California has seen an increase in wildfires, from Siskiyou County to San Diego.
Southern California played a major role in this operation. About a dozen fires, combined, have consumed more than 26,000 hectares of various areas in the region in the past week, in the remote part of the island and in the mountains below the border roads. Six people were injured and around 45,000 others were told to evacuate. At least one house has burned.
This level of activity may seem unusual for May, but experts say, increasingly, that is no longer the case as climate change pushes back the first day of what is generally considered peak fire season.
There are currently five fires of 1,000 acres or more burning in Southern California, which UCLA professor and hydroclimatologist Park Williams described as unusual for this time of year but unprecedented according to a dataset of past fires he keeps.
He cited research that suggests that human-caused warming has advanced the start of the fire season by six to 46 days in most regions, mainly by drying out vegetation. So the fact that fire season is starting now in Southern California is well-predicted, given that it’s unusually dry and warm.”
The region hasn’t had this much rain since December – the rest of the rainy season has been mostly dry except for occasional showers, he said. Meanwhile, the Western US as a whole experienced record-breaking heat from January to March, melting much of the mountain’s snow, he added.
Most of the wildfires in California are currently burning during a coastal wind event that has engulfed much of the state, said Battalion Chief David Acuña of the Department of Forestry and Fire Protection. Although the winds weren’t as strong as the Santa Ana events sometimes seen in the fall, they were combining with dry fuels to create dangerous conditions, he said.
The layers of the region are covered with grasses that grow each year and then die, creating what Acuña describes as layering. “You can imagine that all of Southern California is like a haystack right now, waiting for one spark,” he said.
Humans are often the source of that spark – humans start about 95% of wildfires nationwide, and in parts of southern California, that number is believed to be even higher. The state’s largest fire, the 16,942-hectare Santa Rosa Island fire in Channel Islands National Park, is believed to have been started by a shipwrecked sailor who fanned the flames to attract the attention of rescuers. The 1,698-hectare Sandy fire in Simi Valley, which led to many evacuations, may have been started by a tractor-trailer driver who hit a rock and sparked, police said.
Migration has decreased dramatically in Southern California over the past 30 years, perhaps because people have learned to be more careful and population growth has fragmented the area, Williams said.
But the county hasn’t seen a corresponding decrease in the amount of land burned by wildfires or the level of people exposed to fire danger, he said. He pointed out that this is due to the increase in temperature associated with climate change, and the decrease in rainfall, both of which are tropical plants. He also noted that people continue to migrate to slums that are prone to fires due to the lack of housing throughout the country.
Across California, 1,521 fires have burned 48,135 hectares as of Wednesday, compared to a five-year average of 2,163 fires burning 23,867 hectares at this time — far fewer fires but more land, Acuña said. “What that tells me is, we have a lot of fuel on the ground that burns quickly and burns quickly,” he said. “Combine that with warmer temperatures and more wind, and that’s how these fires are growing so quickly.”
Climate change played a role in driving the unusually warm temperatures that helped dry up fuels this spring, though it’s hard to say to what extent without more research, said climate scientist Alex Hall of UCLA, who found that global warming accounted for about 25% of the extreme drought that led to last year’s Los Angeles firestorms.
“Other than that, I think the factors that led to this spectacular fire in Southern California were due to a series of events that we are familiar with in history,” he said. Big fires in the spring often coincide with the end of an unusual drought in the rainy season, and strong winds are also known to increase fire danger, he said.
It’s unclear what the spike in activity means for the rest of the fire season. Some forecasters predict that Northern California will see more than normal occurrences of significant fires due to the drying of crops, but the picture for Southern California is not so clear.
The region tends to experience more damaging fires when the Santa Ana winds blow in the fall, and it is not yet known how frequent or intense those fires will be, or whether winter rains may arrive first in the area.
Still, Hall said, “because of the dry conditions at the end of the rainy season this year and the warm temperatures, we’re not off to a good start.”
