“Temperatures in the area reached 27-below-zero, with wind chills dropping to minus-40 degrees, according to local weather observations provided by police.
With wind chills of 40 below, experts say frostbite can set in in less than 30 minutes.”
It can "set in" a LOT quicker than that. I grew up in Bemidji. I lived just across an athletic field from the college swimming pool, and I was on the swim team. I would get up for morning practice, and run across the field to save time. It was a quick run, so I wouldn't always dress properly for the weather since I would put on a swimming suit when I got there, anyway.
One cold, windy morning, I quickly ran to the pool, jumped into my suit, and jumped into the pool. I quickly jumped right out, again. My ears had frozen, and thawed quickly when I hit the water. It was quite painful. It also took several years before all the lingering effects were gone. I was probably in the cold for only two or three minutes. The run to the pool was into the wind.