ISABELLA — Calmer winds, cooler temperatures and a few moments of sleet and light snow brought encouragement Wednesday as firefighters continued efforts to contain a blaze that was in a “pause mode” — days after it moved at breakneck speeds, swallowing nearly 160 square miles of forest along the Minnesota-Canada border.

The fire in the Boundary Waters Canoe Area Wilderness is one of the largest on record in the state, and just under half of the access points into the wilderness were closed to campers by midday Wednesday. Less than 50 buildings — including cabins — had been evacuated.

Plumes of smoke from the fire drifted into Michigan, Wisconsin and northern Illinois on Tuesday, but the plume had largely dissipated by Wednesday because of the drop in heat and wind, and it was less visible because of overcast skies, said Mary Shedd, a Forest Service spokeswoman in Isabella.

What remained of the plume was expected to continue to move southeast. Officials in southern Wisconsin said the air quality in that part of the state would be unhealthy for everyone until late Wednesday.

The fire, which started with a lightning strike Aug. 18, took off quickly earlier in the week, as 30 mph wind gusts ahead of a cold front caused it to spread east. Kris Reichenbach, a spokeswoman for the Superior National Forest, said the fire had “unprecedented growth.”

But by Wednesday, officials were catching their breath.

“Right now it is in a pause mode,” Jim Grant, from the U.S. Forest Service, said of the fire. He told roughly 100 residents gathered at the Isabella Community Center that officials did not expect the fire to move much on Wednesday.

Becca Manlove, a spokeswoman at a fire information line, said 325 firefighters were on the ground as of Wednesday evening, and that 100 more had arrived and would join the effort on Thursday. Manlove said the northwest corner of the fire was looking good. Elsewhere, officials were using airplanes and helicopters to drop water on the fire. Crews on the south end were using bulldozers to clear trees and keep the fire from spreading.

Four National Guard helicopters, two water bombers and an air attack plane from Canada were assisting. Crews also were patrolling the fire’s perimeter and monitoring hot spots.

By Wednesday, fire crews had come in from New Jersey, Montana, Nevada, Michigan, Wisconsin and California, Manlove said.