LYONS, Colo. (AP) - Coffee-colored floodwaters cascaded downstream from the Colorado Rockies on Friday, transforming normally scenic rivers and creeks into fast, unforgiving torrents and forcing thousands more evacuations from water-logged communities beset by days of steady rain.
The relentless rush of water turned whole towns into muddy swamps and brought most transportation to a standstill. Damage assessments were on hold as authorities tried to rescue more than 2,500 people stranded in an emergency that stretched from Colorado Springs all the way to the Wyoming border.
A break in the weather aided crews as they ferried a dozen residents at a time out of Lyons and other mountain towns that had been cut off by high water. The Colorado National Guard tweeted that it helped evacuate nearly 300 people from Lyons and on Friday added helicopter flights to the search-and-rescue efforts, spokeswoman Cheresa Theiral said.
Many roads remained impassable, and still more rain was expected later in the day.
The overflowing St. Vrain River sliced the town of Longmont in half. All major roads were closed, and several thousand homes and businesses were without power.
"This one's going to bring us to our knees," said Tom Simmons, president and co-owner of Crating Technologies, a packing service that had its warehouse inundated. "It's hoping against hope. We're out of business for a long time."
Most of those who were stranded were not in immediate danger. Many chose to stay behind with loved ones or to watch over their property. But some families had been without electricity or running water for two days. Others were low on fuel and medicine.
At least four people have been killed. And the rains forced hundreds of people to seek emergency shelter up and down Colorado's heavily populated Front Range, which has received more than 15 inches of rain this week, according to the National Weather Service.
That's about half the amount of precipitation that normally falls in the foothills near Boulder during an entire year.
Boulder County officials said 80 people were unaccounted for Friday. But, they noted, that doesn't necessarily mean they are missing.
"It means we haven't heard back from them," county spokesman James Burrus said.
Wherever the muddy water gushed, it created an astounding mess and countless inconveniences. In at least one community, the flooding caused sewer grates to erupt into huge black geysers.
The National Park Service closed Rocky Mountain National Park and was escorting people from nearby Estes Park along a trail over the Continental Divide.
About 90 miles of Interstate 25 were closed Friday from Denver to Cheyenne, Wyo., because of flooding on the St. Vrain, Poudre and Big Thompson rivers, transportation officials said.
Boulder officials told about 4,000 people living along Boulder Creek to head for higher ground as debris and mud coming off the mountainsides caused the creek to rise rapidly Thursday night, authorities said.
The creek's waters ran a cafe-au-lait color and began to recede after midnight, but conditions remained dangerous, authorities said.
The entire hamlet of Eldorado Springs, home to about 500 people, was also urged to evacuate because of a flash flood and mudslide threat along South Boulder Creek, Burrus said.
In Fort Collins, neighborhoods along the Cache La Poudre River were evacuated overnight, with the river expected to rise to nearly 2 feet above flood stage Friday, according to the weather service.
The city closed bridges after water began topping Seaman Reservoir in the Poudre Canyon. Residents were warned to stay clear of the river.
By Friday afternoon, National Guard helicopters had rescued almost 300 people who got stuck in the small community of Jamestown, northwest of Boulder. County spokeswoman Liz Donaghey said two choppers were airlifting as many people as they could carry.
Boulder County Sheriff Joe Pelle said he expected to evacuate 2,500 people by the end of the Friday. Supplies were being airdropped to those awaiting help in Jamestown.