LEADING US OFF TONIGHT. MARTHA, THANK YOU. >>> OF COURSE, WE'RE ALSO TRACKING THESE TWO MAJOR STORMS HITTING BOTH THE EAST AND WEST COASTS AT THIS HOUR. A POWERFUL NOR'EASTER MAKING ITS WAY ALL THE WAY UP THE EAST COAST. HEAVY SNOW, RAIN, WINDS GUSTING UP TO 60 MILES PER HOUR FROM PHILADELPHIA TO NEW YORK TO BOSTON TODAY. THE IMAGES COMING IN ALL DAY. LOOK AT THE DANGEROUS DRIVING ON THE HIGHWAYS. CARS STRUGGLING TO STAY ON THE ROAD IN SOME PLACES. NEARLY THREE FEET OF SNOW REPORTED IN PARTS OF UPSTATE NEW YORK, MASSACHUSETTS, AND VERMONT. AND THAT NEW ATMOSPHERIC RIVER HITTING CALIFORNIA AT THIS HOUR. A HIGH RISK OF FLASH FLOODING FROM MONTEREY TO SANTA BARBARA. IN FACT, A RARE ALERT IN LOS ANGELES. GINGER ZEE IS GOING TO TIME ALL OF THIS OUT. AND ABC'S TREVOR AULT ON THE COAST TONIGHT IN SCITUATE, MASSACHUSETTS. >> Reporter: TONIGHT, A TREACHEROUS DRIVE HOME FOR THE MILLIONS IN THE GRIP OF A POWERFUL NOR'EASTER. CARS FISHTAILING IN NEW HAMPSHIRE, PART OF INTERSTATE 93 SHUT DOWN FOR A TIME, POWER LINES BLOCKING THE ROAD. >> WE JUST CAME TO A COMPLETE STOP. AND THAT WAS ABOUT AN HOUR AGO. >> Reporter: CEMENT-LIKE SNOW WEIGHING DOWN TREES -- >> LOOK AT THAT, COMPLETELY OVER THE INTERSTATE. >> Reporter: AND TAKING DOWN POWER LINES ACROSS THE NORTHEAST, PUTTING HUNDREDS OF THOUSANDS IN THE DARK. IN SOME SPOTS, NEARLY THREE FEET OF SNOW ALREADY, WITH HOURS STILL TO GO. >> IT'S REALLY HEAVY, REALLY HEAVY SNOW. HEAVIER THAN USUAL. MOVING IT FEELS LIKE, YOU KNOW, IT'S A WORKOUT. >> Reporter: AT A SNOWY SYRACUSE AIRPORT, A DELTA FLIGHT WENT OFF THE TAXIWAY. FORTUNATELY, NO ONE WAS HURT. >> WE FELT US GLIDE TO THE LEFT A LITTLE A BIT, AND THEN IT FELT AS IF WE WERE KIND OF ON RUMBLE STRIPS SIMILAR TO THE HIGHWAY. >> Reporter: AND ON THE COAST, WINDS GUSTING UP TO 60 MILES AN HOUR. AT HIGH TIDE IN SITUATE, MASSACHUSETTS, OFFICIALS BRACING FOR FLOODING. IS THIS THE WORST STORM OF THE SEASON FOR YOU? >> DEFINITELY THE WORST STORM OF THE SEASON. THIS IS KIND OF THE PERFECT STORM, WITH THE WIND AND THE RAIN, THE SNOW, AND THE TIDES. >> Reporter: AIR TRAVEL DISRUPTED ACROSS THE COUNTRY. MORE THAN 4,000 FLIGHTS DELAYED, AND 1,000 FLIGHTS CANCELED SO FAR. AND DAVID, THESE MASSIVE WIND GUSTS ARE SLAMMING THE WAVES UP AND OVER THE SEA WALL HERE IN SCITUATE. THERE'S ALREADY FLOODING ON THE OTHER SIDE. AND THIS STORM IS GOING TO CONTINUE THROUGH TONIGHT INTO TOMORROW MORNING. DAVID? >> ALL RIGHT, TREVOR AULT IN SCITUATE, MASSACHUSETTS, TREVOR, THANK YOU. LET'S GET RIGHT TO CHIEF METEOROLOGIST GINGER ZEE, TRACKING IT ALL. AND WE BEGIN WITH THIS NOR'EASTER, IT'S NOT DONE YET, GINGER. >> Reporter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