Frost heaves seem worse than usual this winter. Drive along even some of the main state highways and, without warning, you can hit a bump that can give you a jolt, make you bite your tongue, or, if you are in that age group, shake loose a denture.

Only rarely this winter can you see one of those red or yellow warning signs. Randy Grey, superintendent of the Ellsworth district for the Department of Transportation, says his crews have been too busy clearing off snow to bother much with the signs. He hopes to get to it before long. But he says some roads have so many bumps in a row that he may have the crews write an “S” after the “BUMP” or “FROST HEAVE” and just post the sign at the start of a rough patch.

Bill Allen, at DOT in Augusta, distributes the signs around the state. Some want the ones that say “BUMP,” and others want “FROST HEAVE.” Maybe some crews are afraid that tourists from down south won’t have heard of frost heaves. Randy Grey jokes that one means up and the other means down.

Dave Rocque, the state soil scientist, says don’t blame the frost heaves on the depth of the frost this winter, which goes down as deep as nine feet in parts of Bangor. The bulging results from different materials in a roadbed. Some absorb moisture more than others, and they expand at different rates. Even two feet of frost can cause a heave.

But a deeper frost means the heaves will last longer.

This winter’s prolonged freezes have brought a rash of wrecked water mains. Some, as deep as seven feet down, have been crushed by the weight of four or five feet of frozen ground. Earth work contractors say the frost depth varies greatly. Open areas are the worst, while snow cover or forest mulch insulates the ground from the cold. Foresters can scrape away the snow in the woods and find the ground unfrozen.

The contractors don’t let the frost stop them. Their machines can usually dig through it. If necessary, they resort to a jackhammer. A funeral director says that even in a mild winter he waits until spring to dig graves.

For the rest of us, until the ground finally thaws, it is best not to count on warnings. Watch for bulges in the pavement, and slow right down.