Care bags sit ready for people seeking refuge from the intense cold front sweeping over the intermountain West at Denver Coliseum Wednesday in Denver.
CNN  — 

The major winter storm crossing the nation is causing dramatic declines in temperatures across the central US as arctic air pushes south and east.

Some highlights:

Casper, Wyoming

(Mountain time)

In less than 18 hours, from 7:40 a.m. Wednesday to 1:35 a.m. Thursday, the temperature dropped 70 degrees.

7:40 a.m. Wednesday: 28 degrees.

8 a.m. Wednesday: 3 degrees.

Casper dropped 25 degrees in just 20 minutes Wednesday.

1:35 a.m. Thursday: minus 42 degrees

6:00 a.m. Thursday: minus 35 degrees with a wind chill of minus 76 degrees.

LIVE NEWS: Winter storm and severe cold sweeps across the US

Denver

(Mountain time)

Dropped 65 degrees in 16 hours.

12:58 p.m. Wednesday: 50 degrees.

4:58 a.m. Thursday: minus 15 degrees.

The largest plunge came when temperatures dropped 47 degrees in just two hours Wednesday from 46 degrees at 3:58 p.m. to minus 1 degree at 5:58 p.m.