Asphalt paving in every town in Arkansas, from Little Rock

Little Rock sits where the Ouachita foothills run out onto flat land, and the towns around it get both kinds of ground.

Hot Springs is up in the Ouachita Mountains, where rain runs hard down a sloped drive and eats at its edges, while Pine Bluff is out on the flat edge of the Delta. Little Rock's normal freeze dates run from about November 10 to March 21, and its July and August highs average above 91 degrees, so the same surface takes winter cracking and summer softening.

The Arkansas River runs the length of this region, from Fort Smith down past Ozark, Clarksville, Russellville, and Morrilton, with the Ozarks on one side and the Ouachita Mountains on the other.

Ground near the river, or near a lake like Dardanelle, can stay wet long after the rain quits. A base that stays wet loses its strength, so on a valley drive or lot, the first thing to settle is where the water goes.

Most of this region is the flat farm country of the Mississippi Delta, broken by Crowley's Ridge, a line of hills that rises above the fields; Jonesboro and Forrest City are built on it.

Flat ground gives rain nowhere to run. A drive or lot out here needs its own slope built in, toward an edge or a ditch, or the water sits on it and works into every crack.

South of Arkadelphia the land levels out into pine woods on the Gulf Coastal Plain, from Texarkana east to Monticello, with Lake Village and Eudora out on the Delta near the Mississippi River.

Summers here run the hottest in Arkansas, and the southeast gets more rain in a year than the north of the state does. Heat softens asphalt, and soft asphalt under loaded trucks pushes into ruts, so down here the weight a lot has to carry matters more than the ice.

This is hill and lake country: Heber Springs sits just south of Greers Ferry Lake, and Mountain Home lies between Norfork Lake and Bull Shoals Lake.

Freezing weather normally shows up by the last week of October and can last into April, one of the longest cold stretches in the state. Winter and spring are the wettest seasons too, so a crack left open in the fall fills with water just as the freezing starts.

Fayetteville sits at the edge of the Boston Mountains, and north of it Springdale, Rogers, Bentonville, and Bella Vista spread across the Ozark plateau to the Missouri line, with Beaver Lake off to the east.

Summers are the coolest in Arkansas, so heat does less harm here than it does down south. The cold does more: water that gets under a drive freezes and thaws all winter, and that's how a weak spot becomes a pothole by spring.