"It is better to give people a window for evacuations instead of, 'You need to leave right now because the fire is in your backyard, '" Russo said.
As many as 1,300 homes have been evacuated.
Fire officials said the priority for Friday will be to protect structures in the Hermosa area.
The so-called 416 Fire in southwest Colorado had burned almost 17,000 acres (6,880 hectares) by Sunday afternoon, an area larger than Manhattan.
A mandatory evacuation order was issued for 220 residences in the Falls Creek Ranch and High Meadows subdivisions and for residences on the west side of County Road 203 between Trimble Lane and Cometti/Mead Lanes on Saturday, La Plata County Government said.
Neither do the other thousands of people who've been evacuated because of this fire that's sending smoke billowing through the sky and shutting down the San Juan National Forest starting Tuesday.
The fire is now around 10 percent contained, and around one quarter of a mile away from the nearest residential structure.
"It's still a fan on the fire", Oravec said.
As of Saturday morning, the Bureau of Land Management said the Natty Fire was 30 percent contained.
Map of the 416 Fire at 9:15 p.m. MDT June 7, 2018.
No structures have been lost.
Aircraft estimated the new acreage at approximately 10 p.m. Sunday.
The evacuations were issued in anticipation of the fire behavior and wind conditions expected Friday on the north end of the 416 Fire. The combination of weather and fuel conditions created the potential for significant fire intensity and growth.
As of 11 a.m. Friday, a total of 1,625 homes were evacuated and 1,272 homes were on pre-evacuation notice.
"After these evacuations, we know we're in this for the long haul, "La Plata County Commissioner Gwen Lachelt said Saturday night, according to a Durango Herald reporter".
An evacuation center and shelter is open 24 hours a day at Escalante Middle School at 141 Baker Lane in Durango.
Livestock can be evacuated to the La Plata County Fairgrounds at 2500 Main Avenue in Durango. The emergency call center at (970) 385-8700 can help coordinate pick-up of livestock.
Firefighters will continue to patrol along US 550 to mop up hot spots and keep the flames west of the highway and away from structures. Small animals are being accepted at the La Plata County Humane Society, 1111 South Camino del Rio, Durango (970) 259-2847.
A blaze known as the Burro fire prompted U.S. Forest Service officials on Saturday to close part of the Colorado trail in the San Juan National Forest.