Firefighters battling the NCAR fire on the southwestern edge of Boulder significantly increased containment Monday, with the wildfire holding firm at 190 acres.

Containment jumped to 68% from the morning level of 35%, Boulder Office of Emergency Management officials said in an afternoon update.

Brian Oliver, Boulder Fire-Rescue's wildland division chief, earlier Monday credited active direct firefighting, structure protection and the wind shifting in favor of firefighters in helping halt the blaze, which he estimated came only a couple of hundred yards from homes.

Oliver said crews are all around the wildfire, and its forward progress has stopped. Firefighters planned to secure the blaze's perimeter as they worked on containment throughout the day.

The wildfire sparked around 2 p.m. Saturday near the National Center for Atmospheric Research in Boulder and forced evacuations in south Boulder and Eldorado Springs. No one has been injured, and no structures have burned. All evacuations have been lifted as of Monday. Eldorado State Park and some hiking trails in the area are still closed.

About 200 firefighters from 30 agencies jumped on the fire at first, and the interagency effort continues Monday with about 150 personnel.

While the smoldering could last, the active smoke may be gone with Tuesday's storm. Oliver said firefighters could be in the area for the next month as the blaze will likely burn for a long time. Wispy smoke and a nighttime glow shouldn't be a concern to the people in the area, and Oliver said residents should only call 911 if the fire starts to burn in places they didn't see it burning the day before.

The Boulder County Sheriff's Office continues to investigate the cause of the fire, but an update had not yet been given on Monday. On Sunday, incident commander Mike Smith said they narrowed the origin point to the northwest corner of the burn area, but had not determined a cause.

Once crews establish more containment, they'll work inward to keep burning embers from getting picked up in the wind. And while the good amount of snow Boulder has had this winter helped particularly in mop-up of the flames, Oliver said that because the fire has happened so early in the spring, the grass has not had time to green up yet, meaning it is ripe for ignition and only the soil is moist.

"Fire season is year-round now," Oliver said. "It's March, and we just had a 200-acre fire, so the concern is anytime there's no snow now."

Denver Post reporter Sam Tabachnik contributed to this report.