The City of Bend has shut off its water service and is using groundwater wells until officials have assessed damage done by a 300-acre fire raging seven miles from the city.

In a tweet, the city asked citizens to conserve water in the city until the Bridge Creek watershed is fully evaluated for damage.

No new changes were reported by the Central Oregon Interagency Dispatch Center as of 9:43 p.m.

Earlier, officials brought in additional manpower and equipment to battle the Two Bulls wildfire currently raging in Deschutes County.

The fire is estimated to be about 300 acres, up 50 acres from earlier in the day, but the fire's smoke columns are making it difficult to get a precise estimation, officials said.

At least 240 firefighters are now battling the approximately 300-acre Two Bulls Fire six miles northwest of Tumalo.

Nine additional 20-man crews have come to the aid to the original three crews, said Lisa Clark of the Central Oregon Interagency Dispatch Center in Prineville, bringing the total number of firefighters to 240 on the ground. Three water tenders (large trucks that can shoot water further than firefighters can), 13 fire engines and seven bulldozers are now fighting the fire on the ground.

As evening approached, Clark said air efforts will be suspended until dawn.

"Fire behavior tends to calm down as temperatures go down at night," Clark said. "During the day you get the wind and heat of the day, all of that makes the fire more active."

Clark also said that the Skyliners subdivision, a mix of about 20 seasonal and year-round residences, has been evacuated. Earlier the Saddleback subdivision of about 80 homes was evacuated.

The American Red Cross has opened a shelter at Cascade Middle School at 19619 Mountaineer Way in Bend. Volunteers are providing snacks, water and access to disaster physical and mental health services, wrote Julie Miller, spokeswoman with the American Red Cross, in a press release.

At least 240 firefighters are now battling the approximately 300-acre Two Bulls Fire six miles northwest of Tumalo.

Two fires were first spotted at 12:48 p.m. from the Black Butte Lookout Station, but have since merged. The fire is about six miles west northwest of the Tumalo Reservoir near Bend.

Fire information officer Cassidy Kern with the Central Oregon Interagency Dispatch Center in Prineville said that dry conditions and low humidity have greatly increased wildfire risk in central Oregon.

Firefighters have been fighting the 300-acre Two Bulls Fire for most of the day and into the night Saturday. Smoke columns have made air visibility difficult.

Kern said there are nine federal and state fire engines working the fire, as well as two air tankers, two helicopters, three crews and bulldozers. Efforts include dropping fire retardant and ground tactics to contain the size and direction of the fire.

Forest Service Roads 4601 and 4606 have been closed. Officials are urging area residents to be cautious and be ready for an evacuation notice.

A fire information hotline can be reached at 541-550-4850.

--Byron Wilkes