(CNN) A storm system has pounded parts of the Pacific Northwest with strong winds and rain, leaving hundreds of thousands of utility customers without power in Washington and Oregon on Wednesday and saturating the ground -- which could cause more trees to fall.
The storms Tuesday through Wednesday morning were part of an atmospheric river event -- involving rivers of moisture high in the atmosphere -- that has drenched the region for days and caused parts of western Washington their wettest start to a year, according to the National Weather Service.
Flood warnings or advisories were in effect Wednesday morning for ares of western Washington and western Oregon, parts of which received more than 8 inches of rain over the last three days alone.
Strong winds -- including gusts above 60 mph in places -- knocked down trees and power lines. More than 650,000 utility customers were without power Wednesday morning in Washington and Oregon, according to utility tracker PowerOutage.us.
Because one customer can be an entire household, the number of people without power service was likely much higher than 650,000.
"There's a lot of tree and powerline debris on roadways, not to mention standing water, " the National Weather Service's Seattle office said Wednesday morning. "Power outages are causing dark intersections. If you don't have to travel this morning, might be safest to stay home!"
Check the forecast across the country
By Wednesday morning, strong winds were pushing through central Washington and Oregon, and more areas were expected to experience them soon.
More than 11 million people were under high-wind warnings or advisories Wednesday morning, from Washington to the Dakotas and as far south as Nebraska.
High-wind watches are scheduled for millions more people through the Plains for Thursday, the weather service said.