A California Conservation Corps crew sets up burlap tubes called wattles on Tuesday, Nov. 20, 2018, on a charred hill near Paradise, Calif., to slow the rainwater that is likely to be pouring over it soon. (Mason Trinca/For The Washington Post)

The skies were briefly azure over Paradise on Tuesday, a taunting reminder of the mountain air that drew people to settle up here.

But that glimpse of heavenly blue was a temporary respite from the torments that nature continues to bring to this region, beset by the most destructive wildfire in California history. A forecast of three days of rain beginning Wednesday has prompted a flash-flood watch in the central part of Northern California, which might slow the blaze and help clear the smoke-filled air but also could complicate the daunting processes of recovery underway here.

The rain threatens to hinder the search for human remains, wash out tent camps providing shelter to evacuees, and trigger mudflows across the barren landscape, imperiling roads and infrastructure that are critical to the recovery.

A California Conservation Corps crew member places sandbags near Dry Creek in Paradise, Calif. Rain is forecast for the region, which could complicate the search-and-rescue process. (Mason Trinca/For The Washington Post)

California Conservation Corps Crew work on installing wattles near Dry Creek in Paradise. (Mason Trinca/For The Washington Post)

A California Conservation Corps crew member carries a straw-filled burlap tube called a wattle to slow the water and prevent erosion near Dry Creek. (Mason Trinca/For The Washington Post)

“Major fire followed by heavy rain? It’s kind of the worst-case scenario,” said Chris Pappas, a California firefighter working in Paradise who grew up in the foothills.

The risk of flooding is high, he said, if drainage systems are clogged by a mix of ash and other debris, including countless leaves from charred trees. And the ground, Pappas said, hasn’t had a chance to regenerate its ground cover, increasing the risk of mudflows.

“There’s just nothing to keep the soil there,” he said.

On the steep and once-scenic drive from Oroville to Paradise, the roadsides have been sprayed green with a tacky substance in a technique known as hydroseeding designed to hold the ground in place.

Paradise sits on a ridge, with water draining on one side to the Feather River and to Butte Creek on the other.

“Everything goes down from here,” said Cal Fire Capt. Joshpae White.

Huge vacuum trucks are sucking up debris in grates and storm drains, preparing for the downpour. Sandbags have been stacked to redirect water on road surfaces.

It takes only inches of water to move a car, White said.

The rains will also challenge the most macabre effort underway here — identifying the bodies of people who failed to escape Paradise before the flames came through.

The death toll has risen to 81 people. Another 700 remain on Butte County’s list of people unaccounted for.

“It’s a methodical process,” said Jim Mackensen, a public information officer and fire/rescue instructor.

“The bodies,” he said, “are near cremation stage, where you may find ashes and a bone. That’s how hot it was.”

The fire is now 70 percent contained. But it has left much work behind. Mixing rain with those ashes will only complicate the task of figuring out what are human remains.

Search-and-rescue workers search the rubble of a home in Paradise, Calif., on Tuesday. (Mason Trinca/For The Washington Post)

Sandbags protect Pearson Road as California Conservation Corps crews try to shore up hillsides before the rain comes. (Mason Trinca/For The Washington Post)

A process called hydroseeding involves a green substance being sprayed on burned ground to hold the soil in place and prevent mudflows. (Mason Trinca/For The Washington Post)

In many neighborhoods, all that is still standing is a row of chimneys — blackened brick columns surrounded by piles of ash that could turn out to be funeral pyres.

The searchers try to imagine the houses as they were once lived in — figuring out which room is which and where a victim might have tried to hide.

Tuesday afternoon on Pentz Road, William Swarthout, an information technology specialist with California Task Force Four, was moving from charred foundation to charred foundation with two other men, digging and raking through piles of ash.

“Once you touch it, it’s powder,” Swarthout said watching ashes billow gently up as his colleagues raked and dug their way past the few recognizable objects: a sink, cooking pots, bedsprings, a utility meter. Once the rain comes, he said, “We’re afraid it will be soup.”

Swarthout painted an orange X with a zero to show the property had been searched and that no human remains had been found, then moved on.

“You can’t just search the houses where people are known to be missing,” White said. “People were seeking refuge in random homes as they fled.”

Swarthout’s team had examined 40 houses by midafternoon Tuesday, sometimes waiting for a backhoe to scoop off upper floors that had pancaked down. Now they face increased pressure. The rain, Swarthout said, is sure to slow things down.

And mudflows could move or hide potential victims.

A searcher digs through the rubble of a home in Paradise, Calif., in the search for bodies. “You can’t just search the houses where people are known to be missing,” a state firefighter said. “People were seeking refuge in random homes as they fled.” (Mason Trinca/For The Washington Post)

Chris van Horne, a spokesman for the California Conservation Corps, was working with a team of 35, laying out sandbags and long straw-filled burlap tubes called wattles to slow the water and prevent erosion along a road that drops off precipitously down to Dry Creek.

On the steep incline, workers were hustling to hammer in stakes to hold the wattles in place.

Evacuees in the towns below Paradise, many of whom are living in tents, are also wary of impending rain. In a flat field neighboring a Walmart that has become a campground for displaced people, volunteers began gathering wooden pallets Monday to elevate tents a few inches above the ground, which promises to become a swamp.

The rains are putting another strain on human resilience that has already been sorely tested.

Ashley Bradley was providing traffic control for an AT&T crew replacing old cables along the Skyway that runs up from Chico to Paradise with new fiber lines for cable and Internet. The rain would make everything harder, she said.

“But we’ve got to do it,” Bradley said. “We’ll have our rain gear. We’ll be all protected.”

A California Conservation Corps crew members lays out a wattle near Dry Creek in Paradise, Calif. (Mason Trinca/For The Washington Post)