BROOKVILLE, Kan., Nov. 12— Cowboys rode the plains of central Kansas today rounding up cattle trapped by a searing prairie fire that raced over 100 square miles, killing a hunter and endangering a town.

High winds that pushed the flames across the prarie Thursday were also blamed for the fire.

Officials said the winds knocked a tree limb into power lines that fell to the tinder-dry grass.

The flames, out of control for six hours Thursday, burned to within 25 yards of buildings on the outskirts of Brookville, a town of 250 people in central Kansas.

David Weir, 25, of Salina, who was burned trying to open a fence and save trapped cattle, died early today in St. Francis Regional Burn Center in Wichita. His hunting companion, Raymond Gillespie Jr., 26, of Salina, was in seriously injured.