New York (CNN) -- As storm-battered residents came to terms with the extent of the damage Tuesday, organizers of the New York City Marathon were trying to determine if flight cancellations, flooding and power outages would affect Sunday's race.
"We are going to give everyone the time to get here and if they have to cancel, we will give them the chance to cancel up to Saturday," said Mary Wittenberg, president of New York Road Runners, which organizes the race.
Wittenberg had declared Monday that "time is on our side" for the preparations, though she could not be reached for comment Tuesday after Superstorm Sandy barreled through the region.
As many as 2 million customers in the state of New York were without power Tuesday afternoon.
"We are currently focused on recovery efforts, and our thoughts go out to all those affected by the storm," the race's website said Tuesday. "Please stay safe -- we will update you later in the day as more information becomes available."
The group said race officials have been taking "proactive measures to reschedule pre-race events and to accommodate participants affected by Hurricane Sandy."
Up to 20,000 international runners could be affected by flight cancellations or delays, but Wittenberg said the organization has "a number of options to get them into any of our surrounding airports."
Participants unable to reach Manhattan in time for the big race will be entered in next year's marathon, the group said, though entry fees will not be refunded.
The race's "Health & Fitness Expo" is still scheduled to open Thursday despite its location at the Javits Center, which sits within the area of Manhattan that Mayor Michael Bloomberg ordered to be evacuated.
The 26.2-mile course winds across New York's five boroughs, but does not include lower Manhattan, where heavy flooding took place Monday and early Tuesday.
The race is scheduled to begin Sunday morning on Staten Island, where runners will cross the Verrazano-Narrows Bridge into Brooklyn and run through Queens before crossing the 59th street bridge into Manhattan and the Bronx.