Megastorm Sandy chugged across Pennsylvania Wednesday in an arc toward Canada, leaving more than 8 million customers in the dark and $20 billion in damage. More than 40 deaths were blamed on the post-tropical cyclone, including 22 in New York City, officials said. Some 55 miles north of the city, in North Salem, N.Y., an 11-year-old Little League star and a 13-year-old friend were killed when a 100-foot oak tree smashed into the family room of a house, police said. \"Heaven got two all-stars too soon,\" Daniel Seymour, uncle of 11-year-old Jack Baumler, told The (White Plains) Journal News as tears filled his eyes. New York City financial markets were expected to resume trading Wednesday, although big chunks of the city remained without electricity. New York\'s extensive subway system, which ferries 8.5 million passengers on a typical workday, suffered the most devastating damage from floodwaters in the system\'s 108-year history, Metropolitan Transportation Authority Chairman Joseph Lhota said Tuesday. The New York Harbor saltwater that poured into subway tunnels could have corroded vulnerable signal and switching systems, he said, adding water climbed to the ceiling of the South Ferry subway station at the southern tip of Manhattan. He said service would not be restored for at least four or five days. New York City buses began running again Tuesday afternoon. Mayor Michael Bloomberg ordered a ride-sharing program for taxis. The Port Authority of New York and New Jersey said Tuesday night Newark and Kennedy airports -- both major landing and departure points for international flights -- would reopen Wednesday with limited service. New York\'s LaGuardia Airport, where runways remained flooded, would remain closed, the Port Authority said. Gov. Andrew Cuomo said earlier in the day LaGuardia had suffered \"extensive damage.\" Stewart International Airport, 60 miles north of the city, would also reopen with limited service, the Port Authority said. New York, New Jersey and Connecticut reopened many closed roads and bridges. In New Jersey, much of Atlantic City\'s famed Boardwalk was destroyed and the resort city for gambling and conventions was all but submerged. \"The level of devastation at the Jersey Shore is unthinkable,\" Gov. Chris Christie said in a news conference. President Barack Obama -- who signed federal emergency declarations for 10 states and the District of Columbia and spoke with 20 governors and mayors on a conference call -- planned to visit New Jersey Wednesday afternoon, surveying damage with Christie. Christie is a Republican who has been a scathing critic of Obama\'s presidency but who praised Obama Tuesday for his disaster management. Obama and Christie also planned to talk with storm victims and thank first responders, the White House said. Damage from the storm throughout the Northeast could be as much as $20 billion, catastrophe-risk modeling firm EQECAT said. Christie vowed New Jersey would rebuild. \"This is the kind of thing New Jerseyans are built for -- we\'re plenty tough, and now we have a little more reason to be angry after this,\" he said. \"Just what we need in New Jersey -- a chance to be a little more angry.\"