Hotshot team supervisor watches as firefighters get in to position as helicopters drop water during an aerial assault to contain a brush fire in Southern California.

Wildfire season is just getting underway, but the recent heatwave, dry conditions and abundant growth of grasses from heavy winter rains is already spelling danger for California.

According to Cal Fire, more than 19,000 acres of land had been scorched in the year-to-date period through Thursday—representing a threefold increase over of the amount burned in the same period a year ago. The number of fires handled by the state agency is up about 20 percent so far this year from a year ago.

As temperatures topped 100 degrees this week in many parts of California, there were red flag warnings for elevated fire danger. Some desert areas in Southern California were forecast to hit a sizzling 118 degrees over the weekend.

"Brushfire season is underway," Capt. Erik Scott, a spokesman for the LA Fire Department said Friday. "We've seen a rapid spread of small brushfires on high-temperature days."

The wet winter means there's abundant grass growth along hillsides that adds to the wildfire risk. California's rainy season was one of the wettest on record, and followed a six-year drought.

Dry brush was fuel for a recent brushfire in the Mandeville Canyon area above LA's upscale community of Brentwood. It was started when a weed wacker clearing brush produced sparks.

"We haven't faced an amount of annual grasses of this significance in many years," Scott said. "Adding to that challenge is higher accumulations of dead fuel like dead brush, which is due to many years of drought. That dead brush won't come back despite all the rain we've had."

California's wildfire season tends to start in the late spring and goes all the way into the fall. Experts see fire risk likely increasing in the coming months as mounds of snow melt, and exposes more fuels for ignition.

One of the biggest fires currently underway in the state is the so-called Holcomb Fire in Southern California's San Bernardino National Forest. Around 1,200 firefighters and a fleet of air tankers are assigned to fight the wildfire, which started Monday and so far has scorched more than 1,500 acres.