Record cold temperatures forced the governors of Montana and North Dakota to close all elementary and secondary schools in their states late last week.
In both states, schools were closed last Thursday and Friday, according to state education officials.
The frigid weather had earlier prompted school shutdowns in Alaska, affecting as many as one-third of the state’s public-school students. Closings had been reported in 33 of Alaska’s 55 districts, enrolling an estimated 35,000 students, officials there said last week.
The cold air was trapped over Alaska for more than two weeks before moving into the lower 48 states. Accounting for the wind-chill factor, temperatures in some parts of Alaska had dropped to 100 degrees below zero.