Aaron and Emily Sparks spent the last several days trying to decide whether to leave their home in Durham, N.C., for Lancaster, Pa, to avoid Hurricane Florence.

Millions of people are facing uncertainty as forecasters try to predict the storm's path. But the couple have another factor to weigh: When Emily will go into labor.

The Sparks are expecting their second child on Thursday — the day before Category 4 Hurricane Florence is projected to make landfall somewhere on the Carolina coast. By Wednesday morning, they decided they could wait no longer, and hit the road with their 3-year-old.

People across the southeastern U.S. coast, including Philadelphia natives on vacation, are fleeing for safety from the storm's expected catastrophic conditions. Many are heading west — Airbnb, for instance, is encouraging hosts in cities that are inland in Georgia, Virginia and the Carolinas to offer their places at no charge to refugees. Others, though, are headed farther north to family or just to a place that has a better chance of avoiding heavy rain.

Wednesday morning, the Sparkses were driving to Emily's parents' home in central Pennsylvania, after Aaron posted their dilemma on Twitter to get some crowd-sourced advice.

"If she goes into labor on the way up there, that would be a problem, especially with the potential for traffic," said Aaron Sparks, a political science professor at Elon University.

People like Stephanie Ward, who lives in a mobile home in Jacksonville, N.C,  faced a different kind of decision: What do you bring when everything you leave behind might be destroyed?

Ward packed the family's sole car Tuesday night and began driving to Johnstown, Pa., where she was born and raised, with her three young children, husband, and two pets. Some of her neighbors in the coastal North Carolina town decided to wait out the storm, or didn't have the financial means to go far away. Ward decided to bring family photos and any other irreplaceable items she could fit into the crowded vehicle.

"I don't know if it's my anxiety or it's a gut instinct… something's telling me that I'm going to come back and my home is not going to be there," Ward said. "All I could think in my mind are the pictures of Harvey, Katrina, Irma. I don't want to be the person that says they survived instead of [evacuating]."

Then there are those that are taking a slower route to hoped-for safety.

Mike Connor, 37, will be staying in North Carolina for the storm. The Sharswood native started what is supposed to be a round-trip bicycle adventure from Philadelphia to California just 12 days ago. He's hoping to ride his bike as many miles west in North Carolina as he can, using Couchsurfing.com to find places to sleep. Flying back to Philadelphia, he said, was not an option.

"When you do something as stupid as setting off to bike across the country, you don't want to quit after a week," said Connor, who plans to give free comedy and team-building sessions to nonprofits along the way.

"Something as little as a Category [4] hurricane isn't going to stop me," he joked.

Other Philadelphia natives were very happy to head home.

Lindsey Hinkle, 32, said she and her husband started their journey back to Pennsylvania from their Emerald Isle, N.C. annual vacation spot on Tuesday, though their vacation had just begun on Saturday. They'll spend the rest of it in the Poconos instead.

"We were sad," Hinkle said of having to leave Emerald Isle. "We're trying to make the best of the circumstances."