Houston Dam begins overspilling adding more woe to a city already devastated by flooding!

An already-swollen reservoir west of downtown Houston has begun to crest levees this morning, sending an “uncontrolled release” of Harvey’s floodwaters into neighborhoods, and putting the besieged city into “uncharted territory,” according to an official.

The Addicks Reservoir, located about 19 miles west of downtown, will spill over for the first time in history by daylight Tuesday, threatening immediate surrounding subdivisions.

Jeff Lindner, a meteorologist with the Harris County (Texas) Flood Control District, told Fox News the spillover will cause “serious flooding in immediate areas,” starting as a trickle, then becoming an uncontrolled release of water. Second-story homes also will be at risk, Linder added.

Lindner said this does not mean that downtown Houston will necessarily be greatly impacted, but officials don’t fully know what will happen because they’ve never faced this situation before.