Sometimes even the first responders are under siege.

About 100 staff of the American Red Cross in Greater New York have been bunkered at headquarters on 49th Street since Sunday morning, weathering Hurricane Sandy even as they attempt to coordinate and implement relief efforts across New York City, Long Island and Westchester.

The Rockaways, including fire-devastated Breezy Point, are a relief target for the regional American Red Cross based in Manhattan. AP Photo/Frank Franklin II

“We’re working in shifts and sleeping when we can,” said Michael de Vulpillieres, a communications officer for the organization. “This is a massively huge disaster…. We’re not immune.”

On Tuesday morning, Red Cross teams fanned out across the five boroughs to try and assess the damage and pinpoint where more shelters and medium-term housing was needed for people whose homes suffered flooding and fires.

The organization operates a live map of available shelters where food, water and blankets are available. The Rockaway peninsula, which experienced extensive flooding as well as a fire that consumed 80 homes, is a primary focus.

“We’re here to insure that in the coming days and weeks, they have food and water and emotional support,” said de Vulpillieres. “Rockaways was really badly hit with not only flooding but fires that damaged dozens and dozens of houses.”

“This is the largest relief operation in many years,” he added. Nearly 11,000 people spent Monday night in 258 Red Cross shelters in 16 states, with about 2,000 of those in the New York City area. Those numbers are expected to grow as people seek refuge from flooded homes even though the wind and rain has dissipated.

As a result, the organization is looking for volunteers to help run shelters while also planning on bringing in disaster relief workers from around the country. However, with airports shut down until at least Wednesday, it is a struggle to find means of transport. The problem is further exacerbated by the regional scale of the disaster. Red Cross chapters in half a dozen states such as New Jersey and Pennsylvania are also trying to mitigate the wide-ranging effects of the storm.

One consequence of the storm is that Red Cross offices in 16 states were forced to shut down blood drives, leading to a shortfall of 3,200 blood and platelet donations and concerns that the national blood supply would run low.

“Patients will still need blood despite the weather,” said Dr. Richard Benjamin, chief medical officer of the Red Cross on Monday.

Meanwhile, both President Barack Obama and Mitt Romney called for concerned Americans to donate to the Red Cross.

As of Tuesday, the American Red Cross in Greater New York did not have figures yet available for donations coming in but encouraged people to donate to the regional chapter.

“We prefer people to donate where the need is greatest and we’ll have an opportunity to earmark that money,” said de Vulpillieres.