SISTERS, Ore. -

Another packed crowd of Sisters-area residents heard some hopeful news from the lines of the Pole Creek Fire on Monday evening, as the containment figure crept up to 15 percent.

Fire managers told the residents that number, up from 10 percent, could increase substantially if all goes well over the next few days on the nearly 17,000-acre blaze.

However they also said the fire could still grow sizably, due to large amounts of dead and down fuels. They also said the smoke which has caused choking early-morning conditions in Sisters could be visible for weeks -- until a big push of moisture, or even the first snowfall, snuffs it out for good.

The Pole Creek Fire that tripled in size in a day late last week grew by a relatively small amount -- only 500 acres - on Sunday, but authorities said Monday it's now moved to within about five miles of Sisters, a mile closer than last week.

Meanwhile, shifting winds Sunday blew heavy smoke into areas from Bend to La Pine, giving more of the High Desert the watery eyes encountered in Sisters for the past week.

An overnight infrared flight pegged the fire's size at 16,500 acres. The firefighting force grew to 1,100 over the weekend. More than a week after the fire began, officials say they are still investigating what caused it.

The fire did remain active, with some more "short-range spotting," officials said Monday morning, but the weather actually turned in crews advantage, allowing them to reinforce some fire lines, establish others and begin building contingency lines.

Suppression efforts are focused on the north, south and east sides of the fire, with new, secondary containment lines being strengthened and added.

Firefighters also are preparing for the expected warmer, drier conditions through the week, which could again test the containment lines.

"A strong inversion kept smoke low to the ground for most of the day, which permeated several surrounding communities, including Sisters" once again, a 9 p.m. Sunday update said. "Smoky conditions are expected to remain in the area for the next few days due to a temperature inversion over the fire."

The fire now has covered more than 25 square miles. After tripling in size on Friday, Saturday saw the fire grow by "only" about 1,000 acres.

A spot fire on the fire's northeast corner was lined Saturday night, down into Whychus Creek, officials said.

"Fire suppression conditions have improved with the return of an easterly wind flow, coupled with moderate temperatures and higher humidity," Sunday morning's update said.

However, the shifting winds also blew significant smoke into Bend Sunday morning, making the air "unhealthy for sensitive groups," according to the DEQ's Air Quality Index. The smoke was so thick, the city's iconic Pilot and Awbrey Buttes were barely visible from a distance.

But on the DEQ's Wildfire Air Quality Index, based on an 8-hour (rather than 24-hour) reading, Bend was in the "unhealthy" level for all residents and Sisters again was at the worst, "hazardous" air-quality reading, before things began to improve at midday Sunday.

Deschutes County sheriff's deputies also reminded that a large area south and west of Sisters is under a closure order, for public and firefighter safety.

The fire has cost $5.6 million to fight so far, according to Monday's national situation report from the National Interagency Fire Center.

You can find the latest info on the fire, as well as maps and other details, at the InciWeb site, http://www.inciweb.org/incident/3244/

This information was included in the 9 p.m. Saturday update:

Residents in the Crossroads and Edgington/Remuda areas remain under a Level 2, pre-evacuation alert (west of the 16 Road and South of Highway 20 in the vicinity of Sisters):

· Dangerous conditions exist - be prepared to leave at a moment's notice.

· Public safety agencies will keep public updated about when to leave and which routes to take.

· Persons with special needs or in need of assistance should be moved at this time.

· Large animals should be moved at this time.

In the event that there is a need for evacuation, citizens in affected areas will receive a call from 911 Dispatch with a recorded message with specific evacuation information. To receive these messages on cell phones, citizens are encouraged to visit http://www.deschutes.org/9-1-1-Service-District/Citizen-Emergency-Notification-System-%28CENS%29.aspx and register their numbers with the Citizen Alert program.