SIOUX FALLS, S.D. (KELO) — Cold air is on the way back as we head into the weekend.

Following our midweek thaw across KELOLAND, it’ll be back to reality as we head into the middle of the month.

With snow moving through the region via an Alberta Clipper, portions of KELOLAND will receive a fresh coating of snow on the ground. That, combined with colder air coming into the picture, will set the stage for some rather chilly temperatures by day and especially by night.

The word to know here is “albedo.” It’s a measure of how well a surface can absorb heat on a zero to one scale. The bare ground absorbs more heat than it reflects, so its albedo value is lower. Fresh-fallen snow reflects nearly all of the heat that comes down to the surface, so its value is higher.

A recent example of this in KELOLAND can be seen when we compare Sioux Falls’ and Aberdeen’s recent low temperatures. The low on New Year’s Day in Sioux Falls dropped to a very cold -7 degrees, and that was with mainly bare grounds in place. In Aberdeen, where three inches of snow was still on the ground, the low plummeted to -21 degrees. With few exceptions, Aberdeen was able to achieve far colder lows than Sioux Falls thanks to that snow.

Temperatures attempt to warm up by the start of next week, which will eat away at that snow. As long as there’s even a little bit on the ground, however, it’ll still be something to consider.

So the next time we experience a cold night with no snow on the ground, just remember that it could always be worse. We could have snow on the ground that only adds more cold by taking away more heat.