By Daniel Bases

NEW YORK, Oct 1 (Reuters) - As Joaquin strengthened into a major Category 4 hurricane near the Bahamas on Thursday, states along the U.S. East Coast hustled to activate emergency plans developed after Superstorm Sandy slammed the region in 2012, aiming to blunt the storm's potential impact.

New Jersey Governor Chris Christie, whose state took a direct hit from Sandy, declared a state of emergency, warning residents to "be prepared but don't panic."

The governor of North Carolina made a similar announcement, a day after Virginia declared a state of emergency.

"The weather reports are not encouraging," Christie told a press conference, adding he would consider ordering evacuations if necessary. Forecasters are still uncertain of the likely track of the hurricane and where it might make landfall.

White House spokesman Josh Earnest told reporters the Federal Emergency Management Agency had increased staffing at its 24-hour National Watch Center in Washington, D.C. and has teams deployed or preparing to deploy to potentially affected areas.

Sandy was directly responsible for at least 147 deaths in the United States, according to the National Hurricane Center, the second-deadliest hurricane outside of the southern states since Agnes in 1972. More than 650,000 homes were damaged or destroyed when it made landfall on Oct. 29, 2012, devastating parts of New Jersey, New York and other states and leaving roughly 8.5 million customers without power. Damage costs totaled nearly $50 billion.

Christie said he had ordered stockpiling of 20 days of commodities instead of the normal five days and said "slosh modeling" is being done, referring to how deeply a storm surge might penetrate low-lying coastal areas.

Sand dune barriers have been built along many, but not all, beaches in New Jersey, Christie noted.

In Alexandria, Virginia, which sits in a floodplain along the Potomac River, Old Town Ace Hardware by noon on Thursday had sold out of HydraBarrier bags and sand bags, assistant store manager Mark Tantillo said.

The store was also selling a lot of PVC drainpipe extensions to direct runoff away from properties. Customers complained the city was not doing enough to protect homes, Tantillo said.

New York Governor Andrew Cuomo said the state's emergency operation center in Albany opened on Thursday and those in New York City and Long Island will be running by the weekend.

"New York is in a much better position today than we have ever been before, but when it comes to Mother Nature, you can never be too prepared," Cuomo said in a statement.

New York's National Guard mobilized 200 troops to help identify problem areas for debris removal and has plans for an additional 3,000 if needed.

In places along New Jersey's shore, damage caused by Sandy has still not been repaired while thousands of homeowners have either been denied full insurance claims or still not been able to access funds to rebuild.



The consistent message from leaders, at state and local level, was to give citizens fair warning to prepare by going to their websites to review supply lists and action plans.

"We're hoping for the best, but hope is not preparation nor is it a plan," North Carolina Governor Pat McCrory said from his already rain-soaked state.

Supplies of water and batteries have started to run low in states expected to be affected first by rain and then possibly Joaquin.

Sea wall gates were closed in Ocean City, Maryland while in Norfolk, Virginia, Mayor Paul Fraim declared a state of emergency after the state did the same. The port city suspended street sweeping and refuse collection because of the storm.

The first punch of bad weather coming in the form of heavy rainfall will first swell lakes and rivers on Thursday and Friday while the full force of Joaquin will move from the Bahamas up toward the coast of the Carolinas at the weekend.

It is the storm surge coming after saturation of ground and swelling of lakes and rivers that has officials concerned.

Weather models now show that Joaquin, the third hurricane of the 2015 Atlantic season, could lose strength as it moves north offshore Delaware and New Jersey early next week and then heads towards Long Island and New England.

The U.S. Navy has ordered its ships in the Hampton Roads, Virginia, area, home to the Atlantic fleet, to be ready to get under way within 48 hours because of Joaquin's approach.

Virginia Beach, Virginia, was already dealing with a separate weather system expected to dump heavy rain on the resort town ahead of the hurricane's possible arrival.

"Crews are cleaning storm drains and securing tables, garbage cans and beach furniture so they don't become flying objects that can hurt people or damage property," Deputy City Manager Dave Hansen said in a statement. (Additional reporting by Ian Simpson and John Clarke in Washington, Katie Reilly in New York, Neil Hartnell in Nassau, Bahamas, Victoria Cavaliere in Los Angeles, Gene Cherry in Hatteras Island, N.C. and Colleen Jenkins in Winston-Salem, N.C.; Editing by Frank McGurty and James Dalgleish)