The blackout zone has been expanded to cover up to 2.7 million people.

Pacific Gas and Electric expanded its power blackout zone to include 940,000 customers on Saturday, as the extreme weather conditions heightened the risk that sparks from its equipment could ignite wildfires throughout the utility’s service area.

The blackout could affect as many as 2.7 million people, and would be the largest power shut-off to prevent wildfires in California history.

“The next 72 hours are going to be challenging,” said Gov. Gavin Newsom. “I could sugarcoat it but I’m not.

PG&E added 90,000 customers to the intentional power shut-off as forecasts indicated that widespread dry, hot and windy weather is expected to begin moving through the region between 6 p.m. and 10 p.m. Pacific time Saturday and continue through midday Monday. Gusts were forecast to reach up to 80 m.p.h.