A hillside blaze, dubbed the Marlborough Fire, scorched 85 acres Thursday afternoon in Riverside, but it is spreading at a slow pace.
No structures are threatened. The fire is burning during one of the warmest weeks of the year with temperatures reaching into triple digits in Riverside County.
The fire was reported at 10 a.m. in the hills above the Abbey Court neighborhood near Marlborough Avenue and Northgate Street, said Jody Hagemann of the Riverside County Fire Department. It doubled in size within an hour, but was burning at a slower rate as of 11:15 a.m., Hagemann said. Crews reported 20 percent containment as of 1 p.m.
Firefighters from both the Riverside County and the Riverside City fire departments were working to contain the fire and protect structures.
There was no immediate word on what sparked the flames, which caused Metrolink to halt commuter train lines that run near the burn area. Riverside Transit Agency bus service was provided to as an alternative to passengers of Perris Valley Lines 733 and 734, according to Metrolink.
As of Aug. 27, CAL FIRE reported more than 4,600 fires in California so far this year. Those fires scorched 220,000 acres. During that same period last year, CAL FIRE reported 3,525 fires that burned 200,333 acres. California's five-year average through late August is about 3,600 fires and more than 132,000 acres of scorched land.
A report released earlier this year provided a wildfire outlook for the hot, dry summer months in California. The National Interagency Fire Center report said wildfire risk will be high in inland Southern California in July and in parts of Northern California during August and September. The report noted what could be a delayed start to the wildfire season in some locations.
The state is coming off one of its wettest winters in years, which left hillsides covered in grass and other vegetation. That grass will dry out this summer and turn into tinder, providing fuel for rapidly spreading fires often pushed by strong winds.
An increase in the number of dead and dying trees also can exacerbate the wildfire threat, CAL FIRE officials said. An estimated 102 million trees have died in California due to the state's five-year dry spell and bark beetle infestation.
The agency has been urging residents to take prevention steps, such as maintaining 100 feet of defensible space around homes and other structures. Defensible space provides a natural buffer between buildings and grass, trees, bushes, shrubs and other vegetation that can burn.
City News Service contributed to this report.