Two U.S. firefighters engaged in helping to control the wildfires spreading in the Western region of the country have died.  

They died in an airplane crash Saturday in Arizona while conducting aerial reconnaissance over the Cedar Basin Fire near Wikieup, Arizona, according to the Bureau of Land Management.  

“Our hearts are heavy tonight,” the agency said on Twitter.  

Meanwhile, the Bootleg fire in Oregon, which almost doubled in size Saturday from 158 square kilometers (61 square miles) to 308 square kilometers (119 square miles), has affected the power lines supplying electricity to millions of homes in the Pacific Northwest and California. The interruption to the California-Oregon AC intertie power grid comes amid a heat wave in California.  

In an effort to avoid rolling blackouts because of increased demand on a main source of power, California has urged its residents to conserve energy from 4 to 9 p.m.  

In Northern California, two fires dubbed the Beckwourth Complex fire and spread over tens of thousands of acres were only partially contained Saturday.    

With temperatures of 37 degrees Celsius (100 degrees Fahrenheit) and more, conditions are ripe for fires around California to continue. The National Weather Service has issued an excessive heat warning in effect through Monday. Authorities have urged people to monitor alerts issued by local municipalities and be prepared to evacuate, if necessary.  

Vocabulary)

reconnaissance : (Noun) activity of obtaining military information about a place by sending soldiers or planes there, or by the use of satellite

blackout : (Noun) power failure

amid : (Preposition) in the middle of, surrounded by

contain : (Verb) to keep under proper control

Comprehension)

1. In order to prevent blackouts, what does California ask its residents to do?

2. What were the two U.S firefighters doing when their airplane crashed?