Washington (CNN) -- A team of engineers will delay until Wednesday their plans to rappel down the sides of the Washington Monument, a photographer for the contractor said Tuesday, citing bad weather as the cause.
"They plan to start first thing in the morning," photographer Ryan Pratzel told CNN as rain and possible thunderstorms approached.
The engineers will be looking for damage caused by the August earthquake.
"The engineering team and the rappelling team, a combination of people from Denali National Park in Alaska as well as from an engineering firm, will come out of the windows at the 500-foot level," said Bill Line, spokesman for the National Park Service.
"What they will do is do a very close visual inspection to check to see if there are any smaller cracks that were sustained during the earthquake," Line said. Engineers will work "to determine whether those cracks could, in the next couple of years, grow."
Officials need to "get up close" and search for possible damage, Line said.
The concerns stem from the August 23 earthquake, which shook much of the East Coast.
The Park Service said Monday that the interior assessment found the monument is structurally sound.
"The heaviest damage appears to be concentrated at the very top of the monument, in what is called the pyramidion, where large cracks of up to 1-1/4 inch wide developed through stone and mortar joints," said Bob Vogel, superintendent of the National Mall and Memorial Parks. Daylight is visible through some of the cracks, and rain water has gotten into the monument, which could cause further damage.
The difficult-access rappelling team -- which includes members of the firm of Wiss, Janney and Elstner -- will scale the outside of the structure to get a closer look.
They will install climbing ropes and safety lines on all four sides, then clip onto those lines, Vogel said. Weather permitting, they will climb up the pyramidion and then descend the length of the monument looking for exterior damage.
On Monday, the Park Service put on its web page video of the interior of the monument that was shot during the earthquake. It shows park rangers and tourists rushing down the stairs as debris falls onto the observation deck.
The video also shows a ranger, Niki Williams, helping visitors and remaining calm. "She had the presence of mind, she had the composure, to make certain that she got people down to the 490-foot level and started walking down the stairs," said Line. "She showed a lot of courage, in fact, by coming back up to the 500-foot level to collect the last remaining visitors and to ensure their safety and put their safety ahead of her own in order to get everybody out safely. So we're extremely proud of the work she has done."
In a few weeks, after the exterior assessment is completed, the Park Service expects to come up with a timeline to reopen the monument to the public.
The Washington Monument, built between 1848 and 1884, is 555 feet, 5-1/8 inches tall. Its walls, 15-feet thick at the base and 18-inches at the top, are composed primarily of white marble blocks, according to the Park Service.
The monument "is not going anywhere," Vogel said. "It is a testament to the original builders that the monument has withstood not just this earthquake but an even larger one in the late 1800s."
CNN's Sally Holland and Josh Levs contributed to this report.