Toa55/iStockBy MORGAN WINSOR, ABC News(FRESNO, Calif.) — Authorities have rescued dozens of people near a reservoir in California who became trapped by a fast-moving wildfire in a national forest.Local fire departments and law enforcement agencies from Fresno and Madera counties are conducting the massive rescue operation in the Mammoth Pool Reservoir area of the Sierra National Forest, with help from the National Guard. Military helicopters have been airlifting people to safety, including many who had to be taken to local hospitals for treatment, according to a report by Fresno ABC station KFSN-TV.As of early Sunday morning, 163 people had been rescued and at least 20 were transported to the hospital for injuries, including critical burns, officials told KFSN.The operation was ongoing but it was unclear how many more people would need to be flown to safety.Earlier, the Madera County Sheriff’s Office said in a Facebook post Saturday that approximately 150 people were trapped within the Mammoth Pool Campground, where they were sheltering-in-place at the boat launch. At the time, there were 10 people who had reported injuries.Mandatory evacuation orders had been issued for the area, including campgrounds, but there was no safe evacuation route, according to KFSN.Since igniting in the Sierra National Forest on Friday evening, the so-called Creek Fire has exploded to 36,000 acres as a brutal heat wave pushed temperatures above 100 degrees Fahrenheit in many parts of the state. Some 450 firefighters are battling the ferocious blaze, none of which was contained as of early Sunday, according to the California Department of Forestry and Fire Protection.The cause of the wildfire remains under investigation.Copyright © 2020, ABC Audio. All rights reserved.