Washington Monument Crack
A one-inch wide, four-foot long crack was spotted Wednesday in the Washington Monument's pyramidion, near the very top of the 555-foot obelisk. U.S. Park Police Aviation

How bad did the 5.8-magnitude August 23 earthquake damage the Washington Monument? The National Park Service (NPS) will inform the public during a news conference Monday afternoon.

The National Park Service will hold the news conference to offer new details, including plans as to when the iconic structure will reopen to the public.

The National Park Service has worked with an engineering firm since the late-August earthquake struck outside of Mineral, Virginia, roughly 90 miles south of the nation's capital. Together, they have assessed the extent of the damage and what it will cost to fix it.

The monument's elevator system was damaged in the quake and is only operating to the 250-foot level, The Washington Post reports. The system is believed to have been damaged by its counterweights during the tremor.

After Hurricane Irene brushed by Washington - just days after the earthquake - small pools of standing water were found in the monument, the National Park Service said.

What happened was a lot of mortar popped out, so much so that you can see sunlight above 450 feet in the monument, spokeswoman Carol Johnson said at the time.

The park service erected a 100-foot-radius fence to prevent any falling debris from injuring visitors.

Four cracks were discovered in the marble monument just after the quake, but engineers assured the National Park Service that the monument was structurally sound.

Park service spokesman Bill Line says engineers still have yet to complete their work assessing the damages, but that cracks will need to be filled in temporarily as part of the monument's winterization, a process that takes place each year to prevent snow and water from causing additional damage.

Brandon Latham, a mountaineering and rope-rigging ranger from Denali National park in Alaska, was brought in this week to assist the engineers in rappelling down the sides of the monument to conduct a closer inspection.

The Washington Monument was built between 1848 and 1884. It stands just over 555 feet tall with walls that are 15 feet thick at the base and 18 inches at the top.

The obelisk on the west end of the National Mall was built to commemorate the first U.S. president, General George Washington. It is the world's tallest stone structure and the tallest structure in Washington D.C. The Heights of Buildings Act of 1910 prevents any new buildings from surpassing the monument in size or obstructing it from view.

Across Washington, one of the city's other iconic structures has also been closed since the 5.8-magnitude Virginia earthquake. Crews at the Washington National Cathedral resumed work on Monday with a new construction crane after a crane, brought in for earthquake-related repairs, toppled over on Sept. 7, preventing the building from reopening for Sept. 11 anniversary events.