(CNN) Before Hurricane Maria, Amy Davila Sanchez rarely went a day without hearing from her father and sister in San Juan.

In a running "Davila Chat" group text, the relatives in Puerto Rico share messages and photos with Davila in New York and her brother in DC. That's in addition to standing Sunday morning phone calls and spontaneous FaceTime sessions.

Her dad, Puerto Rican radio personality Luis Davila Colon , texted the group in the early hours of September 20, as the Category 4 hurricane made landfall on the island. Things were getting bad and they were hunkering down, he said. Her brother texted back several times, asking how they were holding up.

Then, nothing for more than 24 hours.

The storm ravaged the US territory, leaving most of it without power. As the island was cut off from the rest of the country, some five million mainlanders -- as Puerto Ricans in the continental US are known -- were suddenly cut off from their homeland, and anxious for news of their loved ones. US Supreme Court Justice Sonia Sotomayor did not hear from some of her family members for days after the hurricane struck.

National news reports painted the island in broad strokes, showing a series of battered homes and flooded neighborhoods in unspecified locations. But mainlanders craved hyperlocal detail. Were the roads to Ponce open? Was power completely out in San Sebastian? Do my relatives in Utuado still have a home?

Desperate for information, they formed improvised networks to crowdsource morsels of news about missing loved ones and hard-to-reach areas. With cellular communications shot, Facebook and messenger apps -- WhatsApp, Snapchat, Zello, Facebook's Messenger -- became indispensable tools for sending and responding to appeals for help.

One popular group, Puerto Rico Maria Updates , swelled to more than 165,000 members in a matter of days. What started as a place for posting and requesting information about relatives has become a support network for those struggling with the unknown, founder Patricia Pichardo said.

"Part of the anguish is not being there to help your family," she said. "You go through ebbs and flows where you think everything is going to be fine but then your mind plays tricks on you."

Many expected a period of silence, but not this long. But even those who make contact struggle with feeling helpless as the humanitarian crisis expands.

'There's very little we can do'

The storm hit early Wednesday, and Davila received the first word from her father on Thursday morning: "estamos bien," we're OK, the Facebook message read. Then, silence for five more days.

She used Facebook to search for information on what conditions were like where her family lived, and to share what she learned about power outages and relief efforts.

Finally, on Monday morning, she received a call from her father and then her sister. The conversations were short and frantic, since they didn't know how long the signal would last: updates on family members, requests for relief supplies, and lots of "I love you."

Amy Davila Sanchez, second from right, with her father and siblings.

"Just seeing their phone number pop up on caller ID and their pictures, the emotion was like ten times receiving the best Christmas gift I'd ever gotten," she said. "The emotions on my end are only a sliver of what they're living through and that's part of the anxiety -- the pain and suffering and despair on their end, and there's very little we can do for them."

To cope, she's pouring her energy into relief efforts. An animal lover, she posts updates on how to help pets as well as humans. On Sunday, she traveled to her mother's home in Celebration, Florida, to help with a donation drive. In one day they received seven pallets of goods to satisfy basic needs -- personal hygiene products, canned goods, battery-operated fans and batteries.

She considers herself among the lucky ones -- at least she's heard from her loved ones.

Desperate for information

Ivonne Mercado of Austin, Texas, has been in sporadic communication with some of her family on the island -- but she's still awaiting information about relatives in Barranquitas.

Her aunt and uncle in Caguas have a landline that's been working on and off since Wednesday afternoon, so she knows they're OK, she said. On Monday, a cousin in Carolina responded to last week's Facebook post with news that everyone there is alive. But Mercado wonders about the condition of their homes. Do they have enough food or water to get by? A generator? Diesel for the generator? She has no idea.

Ivonne Mercado still has not heard from Raquel Mercado, second from right, or her children.

And still, nothing from her aunt and cousins in Barranquitas. She's seen videos online of the town that remind her of scenes from the television show "The Walking Dead," minus the zombies, she said. Beyond that, she has nothing to go on.

She said she's tried FEMA's 1-800 number for locating people, to no avail. She's posted on their Facebook walls. She's called and texted but she knows it makes little difference. They need to initiate contact.

"It's a very helpless feeling to be so far way, and all you can do is go buy diapers and bring them to a collection center," she said. "Your homeland has been destroyed, and there's nothing you can do. And you're in your air-conditioned home and you have your food and your water and all these things, while your family members are suffering."

Missing for two weeks

Ernie Morales of Chicago says he hasn't heard from his 85-year-old father in Aguas Buenas since around September 7, as Hurricane Irma passed over the island. That's when the rural, mountainous region in the interior lost power and his father, Roberto Morales, and his wife started living off a generator.

Morales spoke to his father that day and asked if he knew that another storm was on its way. "He said they were just going to deal with the situation at hand at that time."

Roberto Morales' family has not heard from him since September 7.

That was the last time he spoke with his father.

Morales said he's seen reports on Spanish television that about 3,000 homes have been destroyed in the region alone. He even checked Google Earth, trying to find a picture of his father's concrete house, which he hasn't seen in about 10 years.

Morales said his brother in Houston got through to their father's cellphone Monday, but someone else answered before the connection was lost. Otherwise, he is hopeful that Roberto Morales may be able to survive partly by utilizing the natural supply of avocados and yucca growing near his house.

Ernie Morales wishes he could go down and search for him, but he said he realizes he would be just another mouth to feed. Plus, how would he get there? "It's not like I can just walk up to Hertz and rent a car," he said.

Ernie Morales texts relatives for information about his father in Aguas Buenas.

'It's going to get worse'

The helplessness is what gets Mercedes Ortiz-Olivieri. Most of her family is accounted for. Now, she's worried about how they're going to survive.

Two days after the storm, she found out from a Facebook post that her grandmother, aunt and cousins rode out the storm in the home of a boyfriend's cousin in Levittown. Through internet sleuthing, she found the house's address and contacted a neighbor using the walkie-talkie app Zello. The neighbor checked on the house and told her it had not flooded, a temporary measure of relief.

Mercedes Ortiz-Olivieri, second from left, with her family in Puerto Rico.

She got further confirmation on Tuesday as spotty cell service returned to the area. In flooded Levittown, a cousin found the bridge marked with flags -- one of many improvised "Puente las Banderas" -- with Sprint cell service. She called Ortiz-Olivieri in Washington and told her that everyone is OK, but her grandmother's home in Bayview was destroyed.

Otherwise, Ortiz-Olivieri is exchanging brief texts with her father in San Juan, out of concern for conserving his battery life. They share updates on relatives, and he tells her what he needs, mainly food, water, and a generator -- preferably propane to get around the diesel shortage.

She helped with a collection drive in her community that netted eight trucks worth of supplies, she said. But she has no idea when those supplies will reach her loved ones.

"It's just a lot of uncertainty and I don't think a lot of people understand how desperate that feeling is," she said. "This is ongoing. It's bad and because the conditions are deteriorating it's going to worse."