New London — In a crisis, people often take to social media to seek out help.

In the case of Texans affected by Hurricane Harvey, two Coast Guard Academy cadets took crowd-sourced social media posts and turned them into so-called heat maps, showing high density areas where lots of people were reportedly in need of help.

Since Sunday, Evan Twarog, a junior from Keene, N.H., and Gabrielle Auzenbergs, a senior from Shrewsbury, Mass., have sent reports three times a day to the Coast Guard.

The last report went out Friday afternoon. By then, the data included 1,000 cases involving 5,200 people.

It's the first time that crowd-sourced social media has been used in a Coast Guard response effort.

The information has helped Coast Guard searchers and rescuers in the disaster area. Coast Guard pilots referenced the information to help them decide which neighborhoods to respond to when they weren't busy helping critical survivors at known locations.

"It helped us to get a more real-time estimate of the number of people in areas with severe flooding that needed an immediate response," said Lt. j.g. Emily Bogdan, an HH-65 pilot out of New Orleans.

A group of 500 volunteers from around the world have sifted through tens of thousands of social media posts, searching under certain hashtags such as #Harvey, to provide Twarog and Auzenbergs with what they have deemed to be posts from actual people in need of help. The volunteers are from two nonprofits, Standby Task Force and Humanity Road, whom Twarog got connected with through a crisis-mapping project he did last year.

"It would be very easy to construe this as a two-person operation but it's not. We're the messengers. There are 500 people working behind the scenes from all around the world on this and then, you know, it takes people in the Coast Guard to buy in," said Twarog as he sat in front of two computer screens Friday afternoon preparing to send out the last report.

Auzenbergs was at a soccer tournament Friday and was unable to comment for the story.

The majority of the posts are from people in need of rescue. The posts include information such as exact addresses, the number of people in need of rescue and a description of the situation. The volunteers put all that information in a spreadsheet, which they continually updated, and Twarog and Auzenbergs map it using longitude and latitude data.

Twarog said it takes about 10 minutes to turn the raw data into a heat map. The cadets started combing through the social media data at 6 a.m. on Sunday.

"This one popped up pretty quickly, so a 5-year-old girl on a ventilator with no power in a flooded home. That's pretty gut wrenching," Twarog said.

He said the first case was actually a group of nuns who posted from Rockport, Texas, close to where the hurricane made landfall Aug. 25, that they were sheltering in place. Several hours after the storm hit, there was no word from them.

By the time the cadets sent their first report six hours later, there were around 120 cases.

Initially, the pair only sent the reports, which included the maps and raw data, to the Coast Guard District 8 Command Center, which is responsible for Coast Guard operations spanning 26 states, including the Gulf of Mexico coastline from Florida to Mexico. As the week went on, more Coast Guard units expressed interest in the reports.

"It's honestly super exciting to see that the Coast Guard has been so receptive to a new technology, and that they're starting to see the value of this. Because even if we don't make the most of this technology now, if we do in future responses, it's going to save lives," Twarog said.

j.bergman@theday.com