WASHINGTON (CNN) -- Just days after a magnitude 5.8 earthquake cracked the Washington Monument in four places, the National Park Service is trying to protect it from being further damaged by Hurricane Irene, spokeswoman Carol Johnson said Friday.Engineers for the National Park Service are working inside the Washington Monument to "plug holes and catch anything that they can't plug," Johnson told CNN. "We have a group of people who are on ropes up there, trying to pin and plug whatever they can."The engineers are using a flexible insulation called backer rod."They are basically jamming it into the cracks," Johnson said."They are doing what they can and putting this backer rod in and then they are going to go back up and inspect after the storm," she added.One area of special concern -- the most extensive damage to the stonework near the top caused by Tuesday's earthquake."The crack is about 4 feet long and 1 inch wide and in some places wider and you can see sunlight through the crack," Johnson said.The monument is closed indefinitely to the public while engineers assess the damage caused by the quake.Even without the new cracks, the monument would have experienced seepage because of the way it was built, according to Johnson."The anticipation is there will be more water because of these cracks. These cracks allow the water to get directly through and that is why we are doing everything we can to put in temporary waterproofing," Johnson said.However, the water is not expected to compromise the stability of the structure, she said.The first rain bands from Hurricane Irene began hitting the South and North Carolina coasts Friday. The storm is expected to near the D.C. area Saturday night into Sunday.

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