With Hurricane Florence poised to lash and drown the Carolinas this week, a Houston man whose cellphone app helped rescue 37,000 people last year is gearing up to let residents aid each other once again.

Matthew Marchetti's mapping program — fittingly dubbed CrowdSource Rescue — is an Uber of sorts that connects civilian rescuers with people in need. Since its inception during Hurricane Harvey, Marchetti and his organizing platform for spontaneous volunteers have gained international acclaim as researchers and emergency managers work to streamline evacuations during major hurricanes, like the one looming this week in the Atlantic.

CrowdSource Rescue has been activated eight times, including in hurricanes Harvey, Irma and Maria. More than 13,500 people — including 780 people with first-responder training — have signed in to voluntarily evacuate more than 37,500 people who were otherwise trapped or stranded, most commonly by high water.

Local first-responders, like firefighters, still play a key role in disaster response, Marchetti acknowledged. But with a population experts say is woefully under-prepared for disasters, officials are including Marchetti and others into the equation of how to better use so-called spontaneous volunteers.

"We are not necessarily a traditional response agency. We empower people who are already doing great things," Marchetti, 27, said in an interview with The Arizona Republic. "Ultimately, it comes down to there being this spirit of volunteerism."

'Zero to 120 overnight'

While out for a rainy bike ride the Sunday Harvey hit Houston in August 2017, Marchetti came upon an unfolding rescue scene. He told a firefighter that he used to be an EMT and that he wanted to help but was ultimately told to go check in at the fire station.

That wasn't really an option. Marchetti, who worked in real estate as a data developer, was reliant on his bicycle after he wrecked his car ahead of the storm's arrival, and his transportation options were limited.

Instead, he and a couple volunteers tried using Facebook to get involved in the rescue process. The reports were overwhelming of people checking in and posting updates about being stranded as torrents inundated parts of the city.

With 911 systems overwhelmed and a lack of organized efforts to corral and dispatch civilian rescuers, Marchetti resolved to do something about it.

That night, Marchetti built a basic online mapping program to give a handful of volunteers — mostly people he knew — a place to coordinate their rescue efforts. At best, Marchetti thought, people from his church could use it to try to get into neighborhoods to help, connecting elderly people with vetted rescuers.

He woke up the next day to 1,200 volunteers having signed up.

The map set the internet ablaze as the day went on.

Officials called on those with boats to help their neighbors. The Cajun Navy, a flotilla of civilian rescuers who volunteer during hurricane evacuations, descended on Houston and outlying coastal areas.

Marchetti's map became the go-to organizing force for civilian rescuers.

The platform spurred more than 30,000 rescues by approximately 8,000 rescuers, he said. He then created another outlet for the quick succession of storms that followed: hurricanes Irma and Maria.

“It’s still a little bit odd to me," Marchetti said. "We went from 0 to 120 overnight and haven't really stopped.”

'It was a cluster'

Nick Terrell was one of those spontaneous volunteers during Harvey.

He and some other volunteers spent an entire day driving around Houston, checking Facebook and trying to find a place to put a boat in the water and assist people in need. But every corner they turned was a dead end or an area that had already been evacuated.

They knew people were in need. They just didn't know where.

“We were just trying to help," Terrell said Monday. "It was very unorganized since it was just based off of social media posts. We didn’t know what to do, or where to go, or who to contact to help or anything.

"It was a cluster."

Terrell's wife attended church with Marchetti and learned about his online map. She suggested Terrell check that to see where the need actually was.

The answer: Port Arthur, Texas.

There, he and a team of volunteers set out to help. Some were skilled in emergency medicine or trained as first responders, others only had a boat and an eagerness to serve.

"It was literally overnight a complete 180," Terrell said.

Welcomed into rescue worlds

Something else has happened in between the disasters: Marchetti attained something of a superstar status among those in emergency-management circles.

In July, he spoke to a room of internationally renowned disaster experts who gathered in Colorado and used his experience as an example of what a new perspective on volunteerism can look like during emergencies.

“Volunteering in a disaster is one of the compassionate moments in America," Marchetti said. "That’s when we see true goodness and true justice come out in droves.”

Some emergency officials are working with him to figure out how to leverage the platform's potential ahead of an emergency. If they can have agreements in place and a legion of volunteers ready to perform non-technical rescues in large-scale Harvey-esque events, more highly trained first-responders can focus on those in more dire situations.

Others are working to iron out how the data that's collected — addresses for evacuees in need or contact information for volunteers — can be used down the road to harness the volunteers when response turns to recovery.

“We’re really excited that we’re even at the table,” Marchetti said.

Why it helps

Though FEMA administrator Brock Long has stopped short of recognizing Marchetti's efforts directly, he has consistently advocated for a "culture of preparedness" and a less-bureaucratic system of disaster response and recovery.

His comments came after The Republic in February reported that thousands of the most highly skilled rescuers incurred $92 million in expenses during responses to hurricane-hit regions of the country — often where they sat idle and awaited rescue orders.

All told, those 6,000 rescuers were involved in saving or assisting nearly 9,000 people, raising questions about how to more efficiently use the network of versatile, highly skilled first responders.

"FEMA is just one part of the team," Long wrote earlier this year. "During a disaster, citizens in the impacted communities also become the 'first responders.' We need to empower individuals with life skills to help speed the response and recovery efforts."

Responding to Florence

Hurricane Florence, which intensified dramatically from a Category 1 to a Category 4 hurricane on Monday, could roar ashore with winds of up to 150 mph Thursday or Friday, according to the latest forecast from the National Hurricane Center.

The most recent Category 4 storm to hit the U.S. mainland was Hurricane Harvey last year, which hit Texas with winds of 130 mph. While the damage at landfall was catastrophic, most of the deaths and damage from Harvey were from the tremendous, record-shattering rain that fell across the Houston metro area, which caused disastrous flooding.

AccuWeather meteorologist Brett Rossi said the ground in North and South Carolina and Virginia is already saturated from recent rains. Rivers are high, and the storm will be moving slowly when it arrives, exacerbating the situation, Rossi told USA TODAY.

"This is very scary rain event potentially setting up this week," Rossi said. "Florence could dump a foot of rain in places that cannot handle it, making for a very scary flooding situation in some areas."

Some portions of the Carolinas could see as much as 30-40 inches of rain from Florence, the National Weather Service said, which would lead to river flooding that "could last for days or weeks" after the storm.

Marchetti and his team of volunteers have been bracing for the latest test to their platform, building connections in civilian and sworn emergency services. They've been working to get the word out about the program as Florence churns off shore.

"This could be a big moment," he said Monday night. "It's going to force us to be ready."

To volunteer or learn more about CrowdSource Rescue, go to crowdsourcerescue.com/hurricane-florence

Reach the reporter at 602-444-8515, jpohl@azcentral.com or on Twitter: @pohl_jason.

READ MORE: