Heavy flooding that began last week in Colorado has killed at least four people and completely destroyed approximately 1,500 residences. Some people in the mountain communities above Boulder were trapped by the floodwaters, making aerial evacuations necessary:

Helicopter searches and airlifts resumed Monday as the sun broke through the clouds over the mountains. Rainy weather had kept the helicopters grounded most of the day Sunday and early Monday.

On Sunday, military helicopters rescued 12 people before the rain, and 80 more people were evacuated by ground, Colorado National Guard Lt. James Goff said. . . .

Major road were washed away, small towns like Glen Haven were reduced to debris, and key infrastructure like gas lines and sewers systems were destroyed. That means hundreds of homes in Estes Park alone could be unreachable and uninhabitable for up to a year.

Lyons was almost completely abandoned. Emergency crews gave the few remaining residents, mostly wandering Main Street looking for status updates, a final warning to leave Sunday.

Most of the town’s trailer parks were completely destroyed. One angry man was throwing his possessions one by one into the river rushing along one side of his trailer on Sunday, watching the brown water carry them away while drinking a beer.

Rescues continued through the rain in any way possible, including by foot, all-terrain vehicles zip lines rigged to hoist people and pets across swollen rivers and creeks.

Even Estes Park’s historic Stanley Hotel, a structure that was the inspiration for Stephen King’s “The Shining,” suffered damaged, despite its perch on a hilltop overlooking the town and the river.

Front desk worker Renee Maher said the ground was so saturated that water was seeping in through the foundation, and had caused one suite’s bathtub to pop out “like a keg,” Maher said.

The massive Estes Ark toy store, meanwhile, was high and dry. The two-story business designed to look like Noah’s Ark was closed temporarily because of the surrounding flooding.

“Soon it’s going to be our only way out,” joked Carly Blankfein.

Associated Press

One Estes Park group was rescued by a cat:

Jezebel the cat jumped on a sleeping Jon Johnson, batted his face and yowled until he woke up to find the Big Thompson River spilling into the cottages he and his wife Deyn rented to Estes Park visitors.

They ran from cottage to cottage, knocking on doors and shouting to the sleeping occupants, “Purse! Keys! Medicine! Go!”

The water rose from Deyn Johnson’s shin to her knee in less than a minute. Everybody was safely evacuated before the river swept three of the cottages away and knocked three more on their sides.

She lamented the loss of the Whispering Pines cottages, which they have run since 1993, but praised Jezebel for her swift action.

“We had no warning other than the cat,” Johnson said. “She is going to be treated like a queen for the rest of her life.”

Associated Press

The community of Jamestown was also isolated by the floods, and residents were careful to keep track of one another as they awaited rescue:

Since the catastrophic flood of Little James Creek in the darkness of early Thursday morning, they’ve been checking on each other. They’ve been sharing information, pooling resources and, above all else, counting heads.

There were almost 300 of them until Friday, when military helicopters evacuated all but about 20 from this mountain town northwest of Boulder.

Jamestown lost one person, 72-year-old Joey Howlett, a beloved town fixture who was crushed inside his house by a mudslide Thursday morning.

For days, Jamestown was an inaccessible island in an epic swirl of floodwaters that crushed and mangled buildings and cars, but somehow the town remained undaunted. In Jamestown, there was only one inventory that really mattered in those first terrifying days — its people.

Leyla Jacobs left town Friday on a Chinook because she has to get to her job and her son Brandon has to attend high school in Boulder.

Before the evacuations — 25 people per helicopter, she said — everyone had been walking around town, watching homes and town buildings collapse into torrents of water, mud and rock.

“There was a calm that was unbelievable,” Jacobs said. “You’d meet people just walking around trying to help. You could not tell the people who had just lost everything from the people like us, who were fine. Our house was fine.

“I never felt a sense of panic — just community,” she said in a telephone interview Sunday with The Denver Post.

No panic, but there was horror. Thursday had been a nightmare in living daylight.

“We watched, one by one, houses cracking off and going into the creek,” said Colleen Williams, chief EMS officer with the Jamestown Fire Department. “But everyone was accounted for — that was the best thing.”

Associated Press

The flooding resulted from a mass of moist air that became trapped against the foothills of the Rocky Mountains:

In semi-arid Colorado, the problem is usually too little rain that leads to drought and wildfires. But when the skies open up, the potential for the biggest drenching lies along the Front Range, where the eastern foothills meet the plains and most of the state’s population lives.

Under the right circumstances, a moist air mass can hit the foothills and get stuck. Moisture turns into rain — in the winter, snow — and just keeps falling. That’s what happened last week, when a storm system parked itself over a big swath of the state with so much embedded vapor that forecasters described it as tropical.

Colorado is far from tropical moisture sources, meaning those factors come together rarely, perhaps once every 10 to 15 years, said Nolan Doesken, the state climatologist at Colorado State University.

It’s difficult to predict monster storms, meteorologists say, and early computer models forecast 3 inches of precipitation would fall from the statewide system. That amount alone would be “a big deal” for dry Colorado — a big fraction of its annual rainfall, Doesken said.

“That far in advance, you couldn’t say it was going to be Boulder Creek, St. Vrain, Poudre,” he said, naming several flooded waterways. “You just knew there would be ingredients in place for substantial precipitation for the parts of the state that would be vulnerable.”

But then all that moisture bumped against a sprawling, counter-clockwise wind pattern that pushed it repeatedly up the slopes of the foothills. It condensed, fell as rain, and then the cycle repeated.

In Boulder alone, the system dropped a record 9 inches between Wednesday and Thursday evenings, smashing the old record of 4.3 inches. By week’s end, Boulder County had as much as 15 inches in some areas.

Associated Press

For more information, including closures and official phone numbers, consult this map from Google Crisis Response.