"It's called 'black ice' because it tends to look like the rest of the pavement on the road, although in reality, it's actually clear," the US Forest Service notes. "Black ice forms without creating bubbles, which allows it to blend in with any surface it forms over. Black ice is dangerous precisely because it's hard to detect."

Precip may start as rain, but as temps fall to the freezing mark after sunset Monday, a transition to freezing rain and sleet is expected.