(CNN) -- Monday, it was the pool. Tuesday, Myra Murray took her family to a recreation center.
"We've just been going from place to place with the kids, just trying to give them some way to cool down ... and now to eat," Murray told CNN affiliate WJLA-TV.
She spoke at one of the six sites District of Columbia Mayor Vincent Gray opened to distribute boxed lunches to residents, many of whom lost the means to prepare meals and saw refrigerated items spoil.
Some of the millions without power after deadly heat-driven storms struck the area Friday flocked to malls, libraries, pools and most any other public place with electricity to seek relief from a massive heat wave blanketing much of the nation.
As of Tuesday evening, about 1.2 million customers scattered across 11 states, from Indiana to Delaware, had no electricity, down from about 1.8 million overnight -- and a peak of 4 million on Friday night and Saturday, just after the storms hit. A household is considered one customer, so the actual number of people without power is higher.
The total included some 326,000 in West Virginia, 291,000 in Ohio and roughly 223,000 in Virginia, along with about 96,000 in metropolitan Washington, D.C. Utility and government authorities said some residents may not get electricity back until the end of the week.
"This has been quite an ordeal," Mayor Gray told HLN's "Evening Express," stressing the need for greater responsibility on the part of the local power company.
"We need a game change. We need to speak not so much about how quickly we restore power, but how do we reduce the likelihood of this happening again in the future," he said.
Extreme heat warnings were issued Tuesday for portion of Illinois, Indiana, Missouri, Kentucky, Ohio and Michigan, with the National Weather Service saying that those areas would be scorched with temperatures near or above triple digits.
Heat advisory warnings were in place for a handful of states, including parts of Nebraska, South Dakota, Wisconsin, Minnesota and Iowa.
Cities and towns in the Midwest, Mid-Atlantic and Southeast have already endured temperatures in the high 90s and above 100 degrees since, in some cases, the middle of last week. It's all part of a system tied to the breaking or tying of more than 2,238 hot weather records nationwide between June 25 and Sunday, according to the National Climatic Data Center.
Frustrations were mounting for many.
Residents of Boone County, West Virginia, said Monday their region was among the hardest-hit, telling CNN affiliate WSAZ-TV they're not getting help.
"We have a pool and we have a generator, but a lot of these people have nothing," said Stacy Peters of the Prenter community. "It makes you want to sit down and cry."
She said, "I know they have a job to do and (power lines) are down everywhere, but you know what? Send somebody down here to check on us. Or set a cooling center up here for us or see if we need water."
The nearby community of Wharton set up a cooling center but said water and ice are in short supply.
"Ever since Saturday, we've had people -- 40, 50, 60 people -- waiting to get some relief and it's just not coming," said Carlos Jarvis of Wharton. "People are in dire straits, really."
About 20 roads were closed in West Virginia on Tuesday, down from a high of about 70 on Monday, said Terrance Lively, spokesman for the state's Division of Homeland Security and Emergency Management. Just after the storm on Saturday, some 680,000 customers were without power, he said.
Some 100 major transition lines went down during the storm, he said, but did not know how many were still down Tuesday.
"This is the worst outage we've ever had," said Jeri Matheny, spokeswoman for Appalachian Power, which serves most of southern West Virginia. She said it's hoped power would be restored to all customers by midnight Sunday. Crews from 11 states were helping restoration efforts, she said.
"We'll end up rebuilding large pieces of an infrastructure system in five to seven days that took decades to build," and crews are working in 16-hour shifts, said Scott Surgeoner, spokesman for FirstEnergy Corp., which covers the state's northern half. He said the company hopes the "bulk" of the 125,000 customers lacking power will be restored by Wednesday night, but some outages will stretch into the weekend.
At least 17 people were killed from Ohio to New Jersey in the derecho, a massive storm packing straight-line wind damage, while another three in North Carolina died in a second round of storms Sunday. Virginia Gov. Bob McDonnell said Tuesday the number of storm deaths in his state had risen from 10 to 11.
Ken Mallette, executive director of the Maryland Emergency Management Agency, compared the damage to that seen after Hurricane Irene last year.
"We got a hurricane punch without a hurricane warning," he told CNN on Tuesday.
His agency is most concerned with 36 critical care facilities, such as nursing homes, that were operating on generator power, he said.
The Pepco power company, which serves the D.C. metro area, drew criticism from many for its response time, but Mallette said, "We're not going to sit here and rate Pepco or any other utility. ... That is one thing that will be dealt with in an after-action issue."
For now, he said, "we're not going to be happy until we have every Marylander back online. ... We have zero tolerance. We want that power back on yesterday."
July Fourth celebrations were canceled in several Maryland locales, including Kensington, Germantown, Rockville and Gaithersburg, officials said. Bone-dry and hot conditions forced fireworks cancellations in other areas.
Traffic lights remain out in many hard-hit locales, including around the nation's capital, yet another reason for headaches.
"A lot of detours, a lot of lights that are out (and) some that are spotty," said Larry Simmons, a frustrated commuter in southern Maryland. "A lot of congestion, a lot of discourteous drivers."
CNN's Brian Todd, Ashley Hayes and Devon Sayers contributed to this report.