California Highway Patrol officers are still investigating the crash, but say the rain-slick roads are the likely cause.
Five people had to be taken to hospitals. None of them had life-threatening injuries, officers said.
Another person was hurt not too far from that accident when an SUV crashed into a building on the surface streets.
Officers said the SUV got into an accident with another vehicle and was propelled into the Amp Shop on Woodman and Ventura Boulevard late Friday night.
One person was treated at scene. The crashed damaged the front of the guitar shop.
Between midnight and 4 a.m., there were 31 accidents reported on Los Angeles freeways, compared with nine during the same period a week ago, the CHP reported.