Those who traveled from the Philadelphia area to Monday's Boston Marathon describe a chaotic and confusing scene after a pair of bombs that exploded near the finish line left three people dead and more than 100 injured.

Locally, some wondered what Monday's horrible events would mean for the upcoming Broad Street Run.

From the scene

Melinda Hill, of Wynnewood, went to Boston to watch her twin sister Leah run. She was waiting for Leah to return to their hotel when she heard the first explosion.

"I'd just talked to my sister, who had just finished, and she was walking back, and we had no idea what had happened, and then I saw people crying and it was just chaos," said Hill. "I mean, it's just shocking. It's just horribly shocking."

Charlie Butler is a freelance photographer from Emmaus, Pa. who was covering the marathon for Runner's World magazine. He was 10 yards past the finish line when the explosion occurred. 

"[I] thought it was fireworks, people with us thought it was a transformer. And we found out later, it was about 15 seconds later, another big explosion," Butler said. "At that point, we were told, 'get off the bridge, get out of here.'"

Butler added the lack of communication turned the aftermath into a confusing scene, especially for those wondering about the well-being of their loved ones.

"I just spoke with some woman who had just finished the race, heard the explosions and knew her dad hadn't finished," he said. "She only found out after the race that he was OK. But for that whole time, she was wondering where he is."

More eyewitness accounts

After Fitler Square resident Mary Pelak crossed the finish line, she met up with a friend who invited her to join her and her family in the Family Meeting Area.

"Soon after we got there, we just heard a huge rumbling sounds," she said. "We started hearing sirens."

Pelak said she couldn't see any smoke and had no idea what had occurred. Then, she said, people started seeing new reports on their phones.

"I felt really shaken up and I felt so thrilled and celebratory when I finished and then it just doesn't matter now," Peelak said. "It took that away from not just me but everyone who's here to do this. This event is so significant to so many people and it's really upsetting."

Pelak said her sister used Facebook to let loved ones know she was safe.

According to NewsWorks content partner NBC10, Philadelphia resident Morgan Little said she just finished the race when the explosion took place.

"I'm OK," she wrote to NBC10.com via Facebook messenger.

Little explained that she heard and saw the blasts.

"I was getting my clothes at the shuttle bus and I heard the boom," she wrote. "I looked up and saw a huge could of smoke."

The 27-year-old wrote it was "terrifying, I immediately thought it was a bombing."

Worrying from afar

David April, co-founder of the Fishtown Beer Runners, said one of the group's members ran the marathon. April has received word she is OK, finishing the race before the explosion.

Security is an afterthought for athletes focused on running those 26.2 miles, he said.

"The last thing on your mind is that something like this will happen," April said. "When something like this does happen, it's just heartbreaking."

Broad Street Run impact

Just a few hours after the blasts in Boston, Philadelphia Mayor Michael Nutter said the city is looking to do all it can to ensure the safety of runners and spectators during the Broad Street Run May 5.

The 40,000 or so runners taking part in that event and visitors to the city will notice definite evidence of increased security, he said.

"We may not be able to prevent every possible tragedy like the situation in Boston," Nutter said during a news conference at City Hall.

"This is a constant effort, trying to stay a step, a half a step, two steps, ahead of what next insane thing that some individual or some group might want to do," he continued. "But you can't always anticipate what someone is going to be up to."

He said Philadelphia officials will analyze all the information and insights gleaned from the fatal explosions in Boston — and put them to good use in Philadelphia.

"There's constant training, there's constant planning that takes place," Nutter said. "We understand in the 21st century, coming off what happened on 9/11, that we're constantly on guard, constantly ready, constantly anticipating that something could happen."

Nutter reiterated Police Commissioner Charles Ramsey's earlier statements that the Philadelphia is on a heightened state of alert though there have been no direct threats to the city, or to the May 5 event.

"We are at elevated alert only from the standpoint of making sure people are being vigilant," said Ramsey, noting that bulletins have gone out to officers to that effect.

Around the same that Nutter, Ramsey and other city officials were addressing the media at City Hall, former Mayor and Gov. Ed Rendell took to Twitter with his reaction to the still-developing story.

"Another act of senseless violence fills us with despair," he wrote. "Let's hope and pray injured survive & praise great work of EMTs & first responders."

The video below comes from an NBC10 story about runners' reactions to the blasts.