SAN DIEGO -- A sinkhole big enough to swallow a midsize motor home opened up alongside the eastbound lanes of Interstate 8 in the College area Thursday, forcing an extended closure of part of the route and snarling traffic for miles.
The crater -- measuring about 20 X 30 feet and 20 feet deep -- was reported on the southern shoulder of the freeway near San Diego State University about 10 a.m., according to the California Highway Patrol.
It was not immediately clear what led to the undermining of the asphalt and the soil beneath it, Caltrans information officer Edward Cartagena said.
The erosion revealed an underground pipe that was part of an irrigation system for roadside landscaping until about 10 years ago, but it was unknown if the defunct water line had anything to do with the problem, he said.
Geologists are also inspecting a 30-inch storm drain that runs under SDSU and the freeway to see if it is leaking and possibly the cause of the hole.
Crews initially blocked three of the five eastbound lanes in the area just west of College Avenue while taking stock of the situation, then reopened the one farthest from the hole around midday.
The closures created gridlock stretching to the west past Interstate 15, the CHP reported. Motorists were advised to avoid the area if possible until further notice.
By 10 p.m. crews had filled the hole with concrete and repaired most of the damage. They hope to finish resurfacing the area above the repair in time for the morning commute.