The following is an excerpt from Yahoo! News, another source reporting on the same news story:
A trick used by ancient Egyptians to exploit cracks in Earth to make tomb-digging easier has come back to haunt the Valley of the Kings, new evidence suggests.
While the natural fractures were followed to carve out burial sites, several instances show, rare heavy rainfall events can flood the tombs. Archaeologists are racing to map and photograph the tombs to better preserve their contents and figure out ways to divert the rain.
Another source reporting on the same story can be found at United Press International