It all began simply: A hand-scrawled sign on a lamp post that read, "Want to volunteer? Meet at City Hall at noon."

Then there was the Facebook page, which cobbled together 19 like-minded friends interested in helping victims of a unique weather system that meteorologists later dubbed Superstorm Sandy.

"Our initial idea was that people would find each other on this page and solve each other's problems," said Tiby Kantrowitz, a Jersey City resident who helped organize the effort.

And then it grew.

"From 19 people it turned into 50 in about an hour-and-a-half," she said.

Now, hundreds buzz in and out of a historic downtown mansion in Jersey City, where a neighboring church donated the building to be used as the group's improvised headquarters.

Born out of what many described as a scarcity of local information and services in the storm's immediate aftermath, the Barrow Mansion is now a hive of volunteer activity that federal agencies like FEMA have looked to for partners.

"We all came together and joined our efforts," said Candice Osborne, a local resident who helped organize relief after Sandy's October 29 landfall.

Coordinated virtually all by social media, the once fledgling effort has burgeoned into a full-scale relief operation that delivers more than 250 meals per day, as well as clothing and cleaning supplies to storm-battered residents. The group also cleans out flood-soaked apartments, while dispatching scout teams to check on the elderly and disabled.

"It's been pretty incredible," said Osborne.

Pulling an iPhone from her pocket, she then thumbed across its cracked screen and opened a Facebook app to give a sense of how the delivery process works.

A request flashed on screen.

Holed up in his stormed-battered home, a Facebook user had asked for dog food and towels "from the volunteer network you are coordinating, if that is possible."

"On it!" Osborne replied, dispatching volunteers to the man's address, while tallying the appeal and recording her volunteers' names in the group's growing database.

Moments later, he wrote again.

"I don't know how to thank you. 10 minutes after my request, I had what I need. An almost magical effort."

With government agencies stretched thin to reach those still reeling in Sandy's aftermath, a patchwork of volunteer efforts like those in Jersey City have cropped up in storm-affected communities across the Tri-State area.

Forged quickly and often with little formal structure, neighborhood groups -- like the Barrow Mansion volunteers -- often prove especially effective by way of their numbers, energy and local knowledge. And at times, they offer victims their only reprieve in disaster-stricken communities.

"It's just one those beautiful heartbreaks," said nurse Katie Vacante, referring to how neighbors help each other in the wake of the crisis.

Bounding up stairs to deliver food in local apartment buildings, Irene Barnaby shares that very sentiment.