The Upper Midwest remains locked in the deep freeze, with bitter temperatures stretching into a fourth day across several states.

The cold snap arrived Saturday night as waves of Arctic air swept south from Canada, pushing temperatures to dangerous lows and leaving a section of the country well-versed in winter’s pains reeling.

Authorities suspect exposure has played a role in at least four deaths so far.

Among the coldest temperatures recorded Tuesday was 35 below at Crane Lake, Minn., a National Weather Service forecaster said early Wednesday.

The coldest location in the lower 48 states Monday was Embarrass, Minn., at 36 below. On Sunday it was Babbitt, Minn., at 29 below, according to the National Weather Service.

Forecasters said late Tuesday that overnight temperatures wouldn’t get that low, but warned it was still frigid: Embarrass, Minn., was up to 15 below by late Tuesday night.

The bitter conditions were expected to persist into the weekend in the Midwest through the eastern half of the U.S., said Shawn DeVinny, a National Weather Service meteorologist in suburban Minneapolis.

In Michigan’s Upper Peninsula, residents woke to a wind chill that made it feel like 35 below. The temperature in Madison, Wis., was a whopping 1 degree above just before midday Tuesday. For northern Illinois, it was the first time in almost two years that temperatures had dipped below zero.

(AP)