More than 500,000 energy customers across the West Coast were without power early Wednesday and one person was killed by a falling tree as severe weather caused by back-to-back powerful storm systems began battering the Pacific Northwest.

A bomb cyclone and an atmospheric river will continue lashing the Pacific Northwest with severe weather conditions, the National Weather Service said.

A 70-year-old tree fell on Wendy Harrington’s home in Issaquah, Washington, and she told KOMO-TV that she thought a whole wall was coming down. “It felt explosive, like there was a bomb going off,” Harrington said. “Everything was just very loud.”