As the snow piles up, concern about roof strength does too.
Alan Lukens with Klingner and Associates told us that roofs in the area are normally built to hold about 20 pounds per square foot.
If the forecasted 20 inches fall that would exceed the amount that many roofs in the area are built to hold.
Lukens says most homes should be fine because those roofs have a pretty good pitch to them.
"They're predicting 25 mph winds and that will help blow snow off roofs so we may not get as much snow on the roof as you do on the ground," said Lukens.
But bigger buildings with flat roofs are the ones that could have issues.
Lukens says the bigger the roof, the less snow will blow off.
If it is a very big roof snow will just blow from one end to the other.
And if there are different layers on the same roof, snow could blow into drifts and cause problems on the lower level.