More than 11 million residents, from the central coast to southern California, were under red flag warnings due to winds that exacerbate fire hazards. And nearly 150,000 customers were already out of power on Tuesday due to a combination of felled trees and power lines, and utilities proactively shutting off power to prevent fires.
Winds at the highest elevation in the High Sierra reached 160 km / h on Tuesday. Strong gusts of more than 50 mph have been reported at San Francisco International Airport.
Several hurricane gusts in the mountains of Ventura and Los Angeles counties in southern California were reported on Tuesday. The cause of the strong winds: The combination of a developing storm off the coast of California and a strong accumulated high pressure in the western United States.
Winds are expected to slow slowly on Wednesday.
On Monday, gusts of over 145 km / h were reported from Sacramento to the bay area, with a gust reaching 160 km / h near Kirkwood, east of Sacramento. A gust of 90 mph has been reported even in Tahoe, with winds well above 60 mph extending up and down the coast.
To put this in perspective, the winds of a Category 1 hurricane are 74 to 95 mph and the Category 2 winds are 96 to 110 mph. This means that gusts in California can reach speeds equivalent to a strong Category 2 hurricane.
According to SCE, “When there is a high risk of a forest fire, we can temporarily turn off the power in your neighborhood to prevent our electrical system from becoming the source of ignition.”
“With almost 80% of the western United States experiencing drought conditions, the area is similar to a gunpowder box,” said CNN meteorologist Pedram Javaheri.
Fires would flourish
Winds can be the strongest wind event of the season, meteorologists say – which can make a fire even more dangerous.
“The combination of dry fuels and winds with tropical storm force can lead to the fall of trees and power lines, so any ignition of new fires will flourish and expand rapidly under these conditions,” said Javaheri.
Many locations in Southern California, including Los Angeles, have not seen measurable rain since late December, meaning the region’s vegetation took more than two weeks to dry.
Southern California has also experienced record heat in recent days, in addition to the region’s growing drought.
And the wind that is expected to hit the region is the type seen only every three years, said the San Diego National Weather Service.
Nearly 30 million Californians, or about 3 out of 4 people in the state, will be able to see strong winds by Tuesday, said Javaheri.
Climate change is adding fuel to the fire
With higher temperatures and less consistent rainfall, forest fire conditions are becoming more dangerous and occurring more frequently. Areas burned by forest fires are increasing in the United States, mainly in the western states.
Annual burned areas in the western United States can increase two to six times from current levels, according to the US National Climate Assessment.
“What is happening in California today is a perfect example of how the forest fire season has increased throughout the western United States,” said CNN meteorologist and climate expert Brandon Miller.
Although wind events in Santa Ana usually occur from October to March, normally, only the first few months have a dangerous fire climate.
“In January, western states should be well into the rainy season and humidity levels should be high enough to keep the fire threat low,” said Miller.
With record fire seasons in recent years, “firefighters in California are no longer referring to a ‘fire season’, but to a ‘year of fires’ as climate change has lengthened the season on both sides. “Said Miller.
A chance of rain
There may be a lot of good news at the end of the week, because as the windstorm moves through Southern California on Wednesday, it could leave a moisture farewell gift, said Javaheri.
A low pressure system developed off the coast can bring milder temperatures and higher humidity values. And the increase in humidity could mean the climate to extinguish the arid southwest region.
In Arizona, Phoenix had a sequence of 242 days without precipitation and Yuma, 110 days, until both cities had rainy days on December 10.
Reducing widespread drought across the region can alleviate possible fire conditions.
CNN’s Haley Brink contributed to this report.