A "wall of water," predicted by the National Weather Service flattened out early Friday morning.
But the flash flood warning for Boulder County continues until 6 a.m. and more rain is expected during the night.
Separately, the NWS has also issued a flood emergency for the Big Thompson Canyon and the town of Loveland, as rain continued to fall there as well. NOAA reported that the Big Thompson River at Drake is more than 4 feet above its flood stage of 6 feet.
Larimer County officials, including Sheriff Justin Smith, warned residents of the Big Thompson Canyon on Twitter and other social media to seek higher ground and the weather service extended the flash flood warning until 8 a.m.
The NWS said in a statement that the floodwaters will continue to rise until sunrise. At 10.55 feet, the Big Thompson was running higher than it did during its deadly flood in 1976 — 9.3 feet.
Meanwhile, Fort Collins city officials closed bridges after a late-night surge on the Poudre River, after water began topping Seaman Reservoir in the Poudre Canyon. The city warned residents to stay clear of the river.
In Boulder, officials announced before midnight that they were tracking a large "wall of water, containing debris and vehicles," as it made its way down Emerson Gulch from the Fourmile burn area .
Gabi Boerkircher, a Boulder spokeswoman, said a drainage gulch at the edge of the Four Mile burn scar that was holding a large amount of water has burst, and released a 30-foot wall of water carrying debris including vehicles.
At 12:30 a.m. Boerkircher said the surge of water seemed to have flattened to between 6 and 7 feet deep. Shortly after that, spokeswoman Sarah Huntley told 7News that the flow in the creek had started to slow.
The surge of water knocked out area sensors monitoring the creek.
She said it is unknown if anybody has been trapped in that debris as it makes its way down to Boulder Canyon.
