Investigators say the wildfire in Mariposa County was started when campers did not fully extinguish their fire.
County officials are requesting the governor and president declare a state of emergency.
There are over 2,200 personnel fighting the blaze that has grown to over 1,600 acres.
Tuesday's weather conditions are better than the previous two days, so firefighters are hoping to be able to make better progress on the fire that is only 15% contained.
The US Forest Service is asking for information on anyone camping in the Plumbar Creek area, where the fire originated over the weekend.