Millions in Northeast and mid-Atlantic face flash floods, while West scorched by heat

Millions of Americans on the East Coast were bracing Tuesday for more heavy rain and the risk of flash flooding — some of it "life-threatening" — as states in the West struggled with another day of record-setting heat.

At least two people died Monday amid strong downpours pummeling states in the mid-Atlantic and Northeast, turning low-lying roads into lakes and saturating the ground.

One woman was killed when a tree fell on her home in Burke, Virginia, southeast of Washington, following days of heavy rain, according to Fairfax County Battalion Chief Willie Bailey.

"This is very rare, very rare," Bailey said. "The tree had fallen into approximately a quarter of the home."

Bailey said it's likely that the tree fell because of the wet weather, according to NBC Washington.

"The roots of these trees have really loosened up," he said.

Another person in Agawam, Massachusetts, died after a tree fell on their home, but it is unclear if weather played any role in the fatality.

About 32 million people from North Carolina through Pennsylvania were under a flash-flood watch Tuesday morning.

Major cities such as Washington, Baltimore and Philadelphia — areas already saturated after heavy rain over the weekend — were all expected to be among the wettest this week.

The National Weather Service said five inches of rain could fall between Monday and Thursday, triggering "potentially dangerous, even life-threatening" floods in the mid-Atlantic region.

"Showers and thunderstorms are expected to increase in coverage and intensity early today," the agency said Tuesday. "This pattern will remain in place through Wednesday, with multiple rounds of torrential rainfall possible. Given saturated soil from this weekend's rainfall, repetitive heavy rain may result in flash flooding."

The weekend's storms broke rainfall records in Virginia and Maryland, saturating the soil, closing roads and sparking several water rescues.

On Monday, parts of Pennsylvania saw flash flooding, with one borough declaring a disaster emergency and Hersheypark, a theme park near Harrisburg, forced to close its doors. The park was scheduled to reopen on Tuesday.

While driving in Schuylkill County, Zachary Reichert was forced to climb to the roof of his car in order to escape the floodwaters.

"I can't swim in the first place, so I wasn't jumping in to those waters," Reichert said. He livestreamed his ordeal on his phone until rescuers arrived.

Elsewhere in eastern Pennsylvania, two women, ages 19 and 22, were swept away in Dauphin County while walking along a creek Monday night. The 22-year-old was able to get out, but the 19-year-old was still missing, reported NBC affiliate WGAL.

The rain was forecast to shift to parts of New England on Wednesday before a cold front is expected to clear it out Thursday.

But while the East was hampered by wind and rain on Monday, about 40 million Americans in other swaths of the country were suffering from record-breaking heat.

Parts of Phoenix set a new daily record with temperatures of 115 degrees Fahrenheit, according to the National Weather Service. Maricopa County public health officials said 155 people died in the Phoenix area last year from heat-caused illnesses like heat exhaustion and heat stroke, according to The Associated Press.

In Houston, automated calls warned locals of the oppressive heat, advising them to seek relief in city cooling centers.

A heat advisory was in effect for west Texas and southeast New Mexico into Monday night, with high temperatures well into the triple digits, the service said. Afternoon school bus service was canceled Monday in Las Cruces, New Mexico, where the mercury climbed to 105 degrees, the AP reported.

In California, the state's electrical grid operator called for voluntary conservation of power Tuesday and Wednesday due to the high temperatures.