Governments across the region on Monday sought to prevent the aftermath of a destructive storm from escalating into a humanitarian crisis as the heat index again slipped into triple digits.

In the District, where more than 40,000 people were still without power, authorities kept many public libraries open late into the day so residents could seek out air conditioning.

The city also shuttered the campuses of its public schools, canceled some programs at parks and recreation centers and worked to refill generators at nursing facilities so residents could try to beat the heat.

Montgomery County officials said two cooling centers remained open, as did four public swimming pools.

Other Maryland jurisdictions and Virginia jurisdictions, including Alexandria and Arlington, were also operating cooling centers and swimming pools to give residents safe havens from the scorching temperatures.

"It is vital that all our citizens take every precaution to protect themselves from the high temperatures still felt across Virginia," Gov. Bob McDonnell said.