A winter storm is snarling travel across the East Coast on Wednesday , causing trouble on the nation 's roadways and delays of up to six hours at airports in the Northeast on one of the busiest travel days of the year . About 30 million people from the mountains of North Carolina to Maine could be affected by the holiday storm . `` The storm in the Northeast continues to develop and is causing long delays and numerous cancellations at D.C. , New York city and Philadelphia airports , along with trouble on the roadways , as snow increases in coverage , '' CNN senior meteorologist Dave Hennen said . `` Most delays and cancellations will occur from late morning through Wednesday evening . '' The silver lining for Thursday morning fliers ? `` By Thanksgiving , the storm will be exiting , and conditions should return to normal , '' he said . Use CNN 's weather tracker . Rain and snow . Travelers are already seeing significant snow accumulations as rain and snow target the Washington , New York and Boston metro areas . `` Roughly 30 miles west of Washington , Philadelphia , New York and Boston will see heavy snow while the cities themselves receive only light amounts , '' Hennen said . Up to 18 inches of snow has fallen in parts of West Virginia as of 2 pm ET , and parts of New England could see up to 20 inches of snow . Thundersnow has been reported around Baltimore , parts of New Jersey and the Hudson Valley in New York . Power outages . Mike Todd , a spokesman for the New Hampshire Department of Safety , said power outages are a major concern . `` This is New England ; this is just another winter storm here , and the complication is just that it 's the holiday weekend , '' he said . `` We caution individuals to drive carefully and slowly . Consider staying put if you 're concerned . Safety first , as always . '' Pennsylvania said it 'll have state police and the National Guard in the state emergency operations center . State officials urged residents to avoid the roads if they can . `` The bottom line is , the less cars the better , the less traffic the better , '' said Cory Angell of the Pennsylvania Emergency Management Agency . `` If you do n't have to go , you do n't need to go . You do n't want to be stuck in a queue for hours and then run out of gas and whatnot . It 's important people realize there are hazards involved with travel , and more often than not , they do n't . '' 10 ways to survive holiday travel . Flights canceled . Airlines had canceled 735 flights and had 4,647 delays `` within , into , or out of the United States '' as of 9 p.m . ET Wednesday , and that number is expected to increase , according to FlightAware.com . ( That website does not distinguish whether flights are canceled or delayed for mechanical , weather or other reasons . ) `` This is not a huge number of cancellations , but due to the holiday , flights will be more full , and there will be fewer available seats to accommodate displaced passengers from canceled flights , '' FlightAware.com 's Daniel Baker wrote in an email . `` We expect thousands of delays that will cause moderate disruption to Thanksgiving travelers , '' he said . `` The delays will begin accumulating early afternoon as the worst of the weather impacts the Northeast and will continue to cascade through the evening . '' The Port Authority of New York and New Jersey , which operates major airports in both states , estimates that 1 % of flights will be canceled at New York 's LaGuardia Airport today , 8 % at New Jersey 's Newark Liberty International Airport and hardly any cancellations at New York 's John F. Kennedy International Airport . Fliers should try to rebook their flights for Thursday , Baker said . United Airlines , Delta Air Lines , American Airlines , JetBlue and Southwest Airlines are waiving rebooking charges for holiday travelers in the Northeast . `` Customers ticketed on American Airlines , American Eagle or US Airways or US Airways Express flights on November 26 to , from , or through ( 18 affected airports ) may change flights without penalty , have the ticket-reissue charge waived for one ticket change , and begin travel as early as November 25 or as late as November 27 under American 's current travel waiver , '' according to an airline release . Midwest affected , too . The Northeast is n't the only region where bad weather is predicted . Light snow is forecast until Thursday in Minneapolis , Chicago and other parts of the upper Midwest . The Northwest is expecting rain , with snow in the mountains . Denver is expecting wind gusts of up to 30 mph on Tuesday and 15 mph on Wednesday . AAA is expecting 46 million Americans to travel 50 miles or more from home during the Thanksgiving weekend , and 90 % of them are traveling by car . That would be the most travelers since 2007 . Drivers should check weather forecasts before setting out on the road , and travelers should also check tire pressure , car batteries and windshield wipers . On the bright side , people traveling by car will probably pay less for gas than in recent years , AAA says . The current average price of gasoline in the United States is $ 2.85 per gallon , 43 cents per gallon lower than the average price at the same time last year .
735 flights canceled , over 4,600 delayed , FlightAware.com reports . Comment: East Coast travelers get hit by snow . Airlines waive rebooking charges for travelers .