Update - 5:17 p.m. - Dominion Virginia Power released the following statement late this afternoon:
"Dominion Virginia Power expects to restore service by Tuesday night for 80-85 percent of customers whose power was disrupted by two days of severe storms at the end of last week. The company expects to restore service to 90-95 percent of affected customers by Thursday night, and virtually all remaining customers by Saturday night. However, it is expected that in areas of the most-severe damage, service may not be restored fully until next Sunday."
Dominion has brought in line crews and other assistance from Texas, Florida, Kansas and 10 other states plus Canada, officials reported in a press release.
Updated storm restoration information is always available through Dominion's Storm Center website.
Dominion Virginia Power estimated more than 250,000 customers remain without power in Northern Virginia as of Sunday afternoon — and it could be nearly a week before electricity is completely restored in Northern Virginia.
Dominion Vice President Rodney Blevins said additional storms on Saturday knocked out power to 55,000 more customers, making this the third-worst power outage in Virginia history.
Nearly 2.5 million people (1.5 million Dominion customers) in Virginia were originally affected
Blevins said more than 100 lineworkers are here or en route from 13 states and Quebec, but the restoration effort will take time. The storm cut a path from Indiana to North Carolina, and many workers in Virginia the company could usually call on have to stay and aid efforts in their own states.
"Of the 1 million that were originally affected, we expect 80 to 85 percent to be operational by Tuesday night," Blevins said. "Ninety to 95 percent should be back by Thursday. Nearly all remaining servers will be restored by Saturday and all by Sunday. We would like to thank customers for their patience. We will be continuing to work around the clock."
Gov. Bob McDonnell said "the scope and scale of power outages affect virtually every region of the state."
"It's going to be many days before some of the power is back on," the governor said in a media call on Sunday afternoon. "I know it is a horrible inconvenience, but it is critical our citizens work well together. Please know we are doing everything we can at the state level. Power companies are doing everything prudent in order to get everything back on. But there is risk of storms that could lead to more outages, so the situation could actually deteriorate."
Temperatures will be in the high 90s, with the heat index of up to 105, through Wednesday, according to the National Weather Service.
The governor said seven fatalities can be attributed to the storm, and more are possible as people cope with the heat. The state has opened 25 shelters and 110 cooling centers.
The state has contacted the Federal Emergency Management Agency to see about assistance but has not made any official plans yet.
State officials also will be meeting later Sunday to discuss possible traffic control situations as people return to work or hit the road for a vacation during the holiday week.
Some possibilities include staggered leave times or lifting HOV restrictions. More information will be available after 5 p.m. Sunday.
The governor said he will be briefed later Sunday on why the Fairfax County 911 system was out of order this weekend. Fairfax County Supervisor Chairwoman Sharon Bulova called the outage "unacceptable."
"I flew up to Fairfax to meet with Supervisor Bulova on Saturday," said McDonnell. "We made immediate inquiries with Verizon." The system was fully restored by 3 p.m. Saturday.
"Verizon had their own storm-related challenges," McDonnell said. "911 is the lifeblood of our emergency system. You don't ever expect it to go down. We just don't know at this point. I want the answers as well. The good news is it working now."
Click for more on phone problems in the aftermath of the storm.