SIOUX FALLS, S.D. (KELO) — If you don’t need to travel, stay home, that’s the message from the South Dakota Department of Transportation as a powerful winter storm bears down on much of the state.

Earlier today, Interstate 90 was closed from the Wyoming border to Chamberlain. Interstate 29 remains open, but the DOT keeps an eye on the state’s northeast corner.

Closing interstates is meant to protect drivers.

Jeremy Glocke of Spring Valley, Minnesota, spent hours driving his big rig on I-90 today, delivering a load to Mitchell.

“I was in the dark most of the way, but then it got lighter, and I was able to see a little better. I saw some trucks in the ditch, some cars in the ditch, but just wet roads.”

Glocke’s 30 years of truck driving paid off. He took it slow and steady.

The interstates give us the safest driving conditions, two lanes, and no oncoming traffic, so the decision to close one down is a big deal.

“We all rely on our interstate systems to get where we are going, freight haulers things like that, we don’t take that lightly, so we are doing a lot of coordinating with the other state agencies like the department of public safety,” said Craig Smith, the director of operations for the South Dakota Department of Transportation.

Boil it down, and two main factors determine if I-29 or I-90 should be closed. Deep snow and high winds

“When you get those heavy amounts of snow where it’s going to cause impassable conditions, we run the risk of stranding vehicles, so when we get deep snow depths along with the winds and the visibility, said Smith.

Ice doesn’t impact like snow and wind because crews can usually treat the surface to make it drivable. During a storm like this, the transportation department will monitor the conditions as best they can around the clock. Those making decisions rely on Highway Patrol troopers and DOT workers on the roads to keep them up to date on fast-changing conditions.