Utility company PG&E said its power lines may have stared two Northern California wildfires over the weekend in extremely windy conditions, the Associated Press reports. The company reportedly notified the California Public Utilities Commission that a worker responded to a fire Sunday in Lafayette, where firefighters told them they believed the contact between a power and communication line might have caused the blaze. About an hour later, another worker went to another fire and saw a fallen pole and transformer. Fire officials told the second worker they were looking at the transformer as a potential cause for the fire. The fires forced evacuations in Lafayette and destroyed a tennis club.

PG&E shut down power for many in an effort to avoid sparking wildfires, but the area where the two fires occurred still had power because it wasn’t designated a high fire risk. A third round of shut-offs will began early Tuesday morning, affecting 605,000 customers, or about 1.8 million people throughout Northern California. PG&E said the outage would last until midday Wednesday, when high winds are expected to pass. PG&E also reportedly told the commission that it didn’t notify about 23,000 customers about the power shut-offs over the weekend, including 500 who had known medical conditions. One man died earlier this month shortly after power was shut off, and the company has been blamed for causing wildfires in the past. PG&E spokeswoman Jennifer Robison claimed the company was also working with independent living centers to determine how best to serve the disabled during the power shut-offs.