Bump. You might even say, double bump.

Potholes are apparently twice as plentiful in the District of Columbia this month as they were in January of last year. They are twice as abundant, that is, according to the method by which Stanley S. Ather counts potholes.

After, a street maintenance engineer for the D.C. government currently specializing in potholes, measures potholes by the amount of asphalt it takes to patch them. This month, the city has already used about 1,000 tons of asphalt to fill its potholes. After noted yesterday. In January 1977 only about 500 tons of asphalt was needed.

After is not the only pothole authority to have observed an upsurge. M. Slade Caltrider, who watches over state highways in the Maryland suburbs, said yesterday that potholes have been at least twice severe this winter as last. The National Park Service has also found considerably more potholes on Rock Creek Parkway and George Washington Memorial Parkway than a year ago, a spokesman said.

The primary explanation given by pothole authorities for this month's proliferation of potholes is meteorological: a recurring pattern of freezing temperatures followed by thaws. Such cycles churn up the pavement, they say, leaving potholes. An additional cause of the pothole phenomenon, they note, has been this winder's unusually moist air.

"It's probably as bad as I've seen if for 10 or 12 years," D.C. engineer Ather remarked, noting that pothole repairs may cost the city government $100,000 more this year. "We've got more than we need right now."

The Whitehurst Freeway was reported to be among the District's most pothole-pitted stretches - a "disaster," After called it. But other thoroughfares, he added, also suffer from large and numerous potholes, including Canal Road between Key and Chain bridges, the 14th Street Bridge's southbound span, Kenilworth Avenue north of Pennsylvania Avenue, New York Avenue east of Bladesburg Road, Blandensburg Road north of New York Avenue, East Capitol Street east of Benning Road and Western Avenue between Connecticut and Wisconsin avenues.

In the Maryland suburbs, according to Caltrider, potholes have posed problems on a number of bridges, such as Woodrow Wilson Bridge, and one some of the older, concrete roadways, such as New Hampshire Avenue near White Oak.

In Northern Virginia, highway engineer Don E. Keith cautioned, however, that counting potholes is risky before spring. "We had roads that completely disintegrated during the spring of last year when it thawed," Keith said. Then he added, "I would predict that this is going to be a bad pothole year."