And it's going to be a busy week. Catastrophe modeling firm AIR Worldwide estimates that Sandy will cause between $7 billion and $15 billion in insured losses—possibly making the storm the third-costliest in U.S. history.

The estimate includes wind and storm surge damage to residential, commercial and industrial properties and contents, as well as automobiles. Additionally, the estimate includes additional living expenses and business interruption. It also takes into account demand surge.

Related: Read PC360 editor Mark Ruquet's firsthand experience of surviving Sandy on Staten Island.

Next: Three agents describe how they are operating on Long Island

Long Island

Many residents and businesses remain without electricity on Long Island, with nearly 850,000 customers without power as of early Wednesday morning.

Massive coastal flooding has destroyed dunes and beaches, buckled boardwalks and carried sand several blocks into the communities. Not to mention the countless homes with flooded basements—or worse, those no longer standing.

Even agents aren't exempt from Sandy's wrath. Kevin Crossley, vice president of AAA New York Insurance Services, lives on the barrier island of Lido Beach (on the south shore of Nassau County near Long Beach) and evacuated to a local hotel. He has been unable to return to his home until the mandatory evacuation order is lifted.

Crossley's agency, located in Garden City, did not lose power, and has fielded claims related to tree damage and from flooded cars. “Sandy is the worst storm in memory,” Crossley said. “Very, very bad and we have only just begun to understand the magnitude of the damage.”

Sandy's path took it inland, south of Long Island's East End, which left residents “lucky.” “We got very lucky with this storm. Had we suffered a direct hit I am sure the coastal erosion would be much more severe as well as tree damage,” said Thomas Crowley, partner at Cook Maran & Assocs. (CMA) and chairman of IIABNY.

Located in Southampton, CMA reviewed its disaster contingency plan before the storm hit. The agency has a generator and a rollover system forwards claims calls when telephone lines are down. “We review the plan yearly,” Crowley said. “We have to be here for these events.”

Twenty percent of the staff reported to the office on Tuesday to field claims and contact clients in the area. One day after the storm, CMA fielded 60 claims calls and anticipates at least 10 percent of its clients to file within the next few days.

Located 50 miles west, the James F. Sutton Agency in East Ilsip lost power during the storm and relied on its generator for power and CSR24 to handle calls. By 11:30 a.m. on Tuesday morning, the agency was up and running.

“I had a call from a longtime client whose vacation home on Fire Island had another home leaning against it,” said James Sutton, president. “His interior sustained significant damage from ocean flooding.”

Just south of East Ilsip, 12 homes on Fire Island were swept to sea and 80 percent of the remaining homes sustained damage. Sutton anticipates that tidal surges along the coast will drive most claims. “Homes have been knocked off their foundations while others have had several feet of water inside their homes,” he said.

Commercially, the agency has received claims related to roof, business interruption and loss of refrigeration.

Next: Agents in New Jersey and Delaware describe their areas and how they are operating

New Jersey

Damage in New Jersey is extensive and the Jersey Shore is devastated. But areas inland weren't exempt. The Phillipsburg area has widespread power losses and tree damage.

Caroline Charron, account executive at Ahart Frinzi & Smith (AF&S) said that friends have been told to expect power restoration after Nov. 7. The agency's Phillipsburg office has been without power. To handle the claims process, clients call the office and leave claim reports on voicemail. Employees—those with power—have retrieved those voicemails from home and called the insureds to begin the claims process.

In case clients show up at the AF&S office, employees have staffed the location—without power. However, the agency has relied on Facebook and Twitter to provide real time information regarding office closures, insurance updates and pictures. Prior to the storm, AF&S posted hurricane precautions and special claims reporting telephone numbers on its website.

AF&S operates another office in Alexandria, Va. Employees were unable to get to the offices on Tuesday because of road closures. AF&H account executive Jill Roth submits this picture from 3rd and G NE streets, Washington, D.C.

In Hamilton (near Trenton), Nottingham Insurance was closed on Monday and Tuesday due to the State of Emergency status. Jack Blair, president, said that his agency regained power around 3 p.m. on Wednesday. Phone lines also were out, but the agency redirected calls to cell phones. “We were in triage-like mode all day today, working many cell phones, returning clients calls and directing them to the respective insurance carriers,” he said.

Staff members texted and called its larger stakeholders and clients to alert them that the agency was closed. Nottingham also updated its website with a a Hurricane alert popup and posted storm-related information on its Facebook page.

Besides Hamilton, the agency has an office in Yardley, Pa., which is still without power. The Yardley staff will report to Hamilton on Thursday if the office remains without power.

Both locations are within 50 miles of the Jersey Shore. So far, claims have revolved around power outages, damage from falling objects, wind damage and roofs. The agency anticipates receiving a large number of flood claims—once clients are able to return to the Jersey Shore to assess the damage. “I truly expect the damage to be epic given some of the video and pictures we have seen,” Blair said. “But the insureds need to get to their respective homes to find out just what happened before moving forward.”

Delaware

David Wilgus, partner and owner of Wilgus Assocs., said his location was on the backside of Sandy and didn't bear the brunt of heavy flooding.

On Monday morning, “the winds shifted from the northeast to the northwest, and that blows the sea away from shore and blows the water out of the bays,” he said. “It was a blessing to us.”

Based in a resort area, the agency insures many second homes around its two locations in Bethany Beach and Lewes. The water receded early this morning and last night and clients have been able to get to their properties and assess damage.

The agency did not lose power, but Wilgus took precautions before the storm, just in case. Staff members unplugged computers and power operations in case of a power surge. Data is stored in a location offsite, so policy information is accessible with an Internet connection.