A sinkhole big enough to swallow a midsize motor home opened up alongside 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 feet in width and depth and some 30 feet in length — 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.
The cause remained under investigation as of late Thursday afternoon.
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.
Two lanes were expected to remain out of commission in the vicinity along with a nearby onramp from Waring Road through sometime Friday afternoon, by which time crews hoped to have the sinkhole filled with concrete and covered again by asphalt, Cartagena said.
To aid commuters affected by the traffic tie-ups just east of Mission Valley, Metropolitan Transit System officials offered overnight parking at Qualcomm Stadium for those opting to avoid the freeway and instead take trolleys to their East County destinations.
Motorists were asked to park under or adjacent to the light-rail depot on the south side of the arena and to be aware that the lot is closed to automotive traffic between 1 a.m. and 4 a.m.
