NEW YORK (CNN) - For much of the Northeast, travel isn't an option today.
Airline and ground transportation systems in three major metro areas have ground to a halt as Hurricane Sandy zeros in on the East Coast.
More than 10 million public transit commuters are without service. Here's what to expect in New York, Washington, Philadelphia, on the railways and in the sky:
Thousands of flights canceled
The storm is wreaking havoc on air travel across the northeast, with ripples around the country and the globe.
There have been more than 8,900 flight cancellations so far as a result of Hurricane Sandy, according to flight tracking site FlightAware.com.
Some 1,300 domestic and international flights were canceled Sunday, according to FlightAware, with more than 6,800 Monday flights canceled.
And with forecasters expecting high winds in the Northeast Tuesday, more than 2,500 Tuesday flights had already been canceled early Monday, according to FlightAware. That number was expected to grow.
All Monday flight operations at New York and New Jersey's three major metropolitan airports have been canceled, according to the Port Authority of New York and New Jersey. The majority of Monday's flights were also canceled out of Dulles International and Reagan National airports in the Washington area, according to Metropolitan Washington Airports Authority.
All Monday flights out of Philadelphia International Airport have also been canceled, an airport spokeswoman said. Flights have been suspended at Connecticut's Bradley International Airport as well.
Check your carrier's site for flight status and for links to notification tools and mobile apps. Keep your phones charged and ready in preparation for power outages, and make a note of reservation assistance phone numbers for your carrier.
Many carriers will allow affected passengers to change their itineraries without penalty. Check the major airlines' advisories here: American Airlines, Delta, United, US Airways, AirTran, JetBlue, Southwest.
The good news is that the hurricane is happening during a slow travel season and airlines canceled many of the flights in advance, minimizing the number of stranded passengers, according to Farecompare.com Chief Executive Rick Seaney.
"Barring significant airport damage, flight patterns should be back to normal by the end of the weekend," Seaney said.
Middle Eastern, European and Asian airlines also have grounded flights in and out of the United States' eastern seaboard as Sandy approaches.
Public transportation shuts down
The massive public transportation systems that get workers and travelers around in big Northeastern cities have also shut down.
New York's ubiquitous subway and bus services came to a halt Sunday night at 7 p.m., and there is no timeline for when service will be restored. The area's Metropolitan Transit Authority Service, which also operates the Long Island Rail Road, Metro-North Railroad (serving Westchester and Connecticut, and the city's Staten Island Railway, has suspended service on those three train lines.
It's rare for New York's massive transit network, the largest in North America with about 8.5 million riders a day, to shut down. The MTA reports it's only the second time the system has been shut down in expectation of a major weather event.
The transportation agency's hurricane plan calls for suspending service in anticipation of winds of 39 mph and higher.
In New Jersey, the suspension of all NJ Transit bus, rail, light rail and Access Link service was complete as of Monday at 2 a.m.
Indoor waiting rooms at major rail hubs, including Newark Penn Station, Secaucus Junction and Trenton Transit Center are scheduled to remain open for shelter during the storm, according to the NJ Transit website.
Second only to the New York system in terms of size, the Washington Metro system will also stay idle on Monday. About 1.5 million people use the Metro each day. It's unclear when bus service and rail service will be restored, the Washington Metropolitan Area Transit Authority said.
"Metro service will only be restored when it is safe to do so," following a damage assessment, according to the agency's website.
The 770,000 riders who use public transit each day in the Philadelphia area will also have to do without. The Southeastern Pennsylvania Transportation Authority also urged those who do not need to travel to stay off the roads. Just like with New York and Washington, it's too early to say when public transit in Philadelphia will be restored.
Train service derailed
Amtrak said it is canceling almost all services on the eastern seaboard Monday.
Bus lines connected to those trains were also canceled. Trains coming to and from Canada or to and from the southern U.S. states will still operate, but stop short of the storm-affected states. Consult Amtrak's website for more details.