The wildfire broke out in Poudre Canyon near the Hewlett Gulch Trail in Roosevelt National Forest on Monday just after 1 p.m.
The fire is about982 acres as ofWednesday afternoon - growing from about600 acres. It is still about 5 percent contained and is growing in the Greyrock area, on the eastern part of the fire.
Erratic, shifting winds caused some growth Wednesday. Persistent winds are expected overnight with winds out of the west at 10 to 15 mph. Gusts could get up to 25 mph.
A firefighter suffered minor injuries on Tuesday night, and was treated and released.
Larimer County says they are mostly concerned with keeping the structures safe. They say the fire has mostly moved away from the homes, but winds can shift that at any point.
Residents from mile marker 110 to 115 - a quarter-mile north and south of Highway 14 - should be prepared to evacuate if needed. About 160 reverse notification calls went out on Tuesday as a precautionary measure.
Authorities sent out a notification on Wednesday to people living in a one-mile radius of Mount Mahogany and Gordon Creek Lane. People living in the area should be ready to evacuate if needed.
"This is early in the season, we've had dry conditions in the state. But certainly we are making sure to take extra care. There's always people in Colorado where there's a fire," Larimer County told 9NEWS Tuesday morning.
The fire is less than one mile from Poudre Park. It's a difficult hike to the fire, and there is limited access through the roads - making fighting the fire difficult to fight. Larimer County says the fire spread quickly after it started in the grasses on Monday. Now, the fire is burning, grasses, shrubs and other types of vegetation.
A Single Engine Air Tanker (SEAT) and Type 1 and 3 helicopters worked on the fire throughout the day Tuesday.
As of Tuesday afternoon, the SEAT had made six drops (4,500 gallons of retardant), the Type 1 helicopter had made 20 drops (11,000 gallons of water), and the Type 3 helicopter had made 20 drops (2,000 gallons of water).
The Hewlett Gulch Trail and the Greyrock Trail are both closed as crews fight fires.
The fire is in an area where there has been at least eight previous fires.
The U.S. Forest Service is posting updates on the fire at http://inciweb.org/incident/2863/.