A huge wildfire has prompted evacuations north of Los Angeles, with firefighters hoping to rein in the blaze before temperatures spike later on Thursday. The Lake fire broke out on Wednesday afternoon in dense forest land in the Lake Hughes area of the Angeles national forest, some 60 miles (97km) north of downtown Los Angeles. The blaze exploded in size within hours on brushy ridges, including some areas that had not burned since 1968, fire officials said. By Thursday morning, the flames had consumed nearly 16.5 square miles (42 sq km) of timber and chaparral shrubland and an enormous plume of smoke was visible across much of southern California. About 100 rural homes were evacuated in the Lake Hughes. Preliminary damage assessments found that at least three structures burned, though it was not immediately clear if they were houses. There was no containment of the fire, but light winds and scattered thundershowers early on Thursday helped calm the flames. The fire was being fed by tinder-dry brush in steep terrain, but its ferocity on Wednesday approached that of wind-driven blazes that usually erupt when gusty Santa Ana winds arrive later in the year, said the county deputy fire chief, David Richardson. Officials were preparing for the possibility of extremely dangerous fires on Thursday as heat increases and humidity levels drop, fire officials said in a statement. The area was expected to have temperatures in the mid-90s (about 35C) or higher through the weekend. Evacuation centers were designated for residents and animals, but because of Covid-19 concerns, people were told to stay in their cars in the parking lots of the centers.