Between 80 and 100 acres of farmland burned during a wind-blown grass fire near the border of Salem and Superior Townships Wednesday and the cause is still unknown.

Salem Township Fire Chief Ed Rohraff said Thursday that the cause of the fire is still under investigation, but the high winds that shook Washtenaw County on Wednesday spread the flames.

“We basically played defense and let it come to us at the road area (near Dixboro Farms Drive),” Rohraff said.

According to eyewitness accounts, the fire began burning before 3 p.m. Wednesday and spread from an area near the border of Salem Township and Superior Township off of Dixboro Road toward a private neighborhood to the north.

One home was evacuated, but the fire never crossed the line of heavy brush and trees between the field and the neighborhood, according to fire officials.

With the fire deep in the middle of the field, it was impossible to send a hose out to fight the flames, Rohraff said. Instead, groups of firefighters worked to beat down the flames and keep them low as they advanced north.

When the flames came within range of the fire trucks stationed in the neighborhood, hoses were able to be used to put out the flames, Rohraff said.

“There wasn’t much we could do,” he said. “When the wind would come up, it would blow the flames 20 or 30 feet up in the air. It was bad news.”

Captain Shaun Bach, of the Superior Township Fire Department, which responded to the fire at the same time as Salem, said his department has dealt with large grass fires before and they usually occur in the springtime.

However, Wednesday's fire was unique in how quickly it spread.

He said his department returned to the field later on in the evening to put out a few hot spots.

Rohraff said firefighters left the area at about 7p.m. Wednesday and all of the homes in the neighborhood were spared.

Firefighters had to take a very different approach to fighting the grass fire than a normal structure fire, Rohraff said. Instead of being able to target the fire immediately with hoses and water, firefighters used brooms to beat down the fire and keep it contained as it moved north.

The wet ground in the field and the sheer size of the farmland made it more difficult to get trucks to the fire, he said.

“You go in on a structure fire with hoses and lines and get to fire,” he said. “You can’t stretch a half mile of hose (to the field) to get the fire out.

" The ground is so unreasonably wet that there’s not much to hold a vehicle up and it gets in bad shape.”

These types of fires are unusual in Salem Township these days, Rohraff said.

While there would be fires caused by trains going through the township many years ago, Rohraff said Wednesday’s fire was the biggest grass fire in 15 or 20 years.

“It’s the first big one that we’ve had in a long time,” he said.

Kyle Feldscher covers cops and courts for AnnArbor.com. He can be reached at kylefeldscher@annarbor.com or you can follow him on Twitter.