Firefighters continue to battle Fork fire in Azusa amid high heat

Temperatures in the valleys could hit 100 degrees Sunday as firefighters continue to battle the Fork fire in Azusa. 

Fire crews on the ground say the heat is a concern as they continue to battle the fire burning just above Azusa and Glendora, which has scorched 330 acres. Two firefighters have been injured. 

It remains unclear what sparked the fire, which erupted Friday afternoon; however, there is a lot of dry brush in the mountains. The fire was 30 percent contained. No structures are threatened. 

Elsewhere, near Tujunga, the so-called La Tuna Fire has burned more than 40 acres and forced the closure of the 210 Freeway briefly. The fire was 90 percent contained. 

Fire crews are urging the public to exercise caution, especially in the mountains, as the heat and the low humidity could spark other fires.