( CNN ) -- Hurricane Isaac contributed to a moist air mass that brought torrential rainfall and street flooding Tuesday in Charleston , South Carolina , officials said . By evening , between 4 and 8 inches had fallen across the low-lying metropolitan area . `` We were stranded and had to be rescued ourselves , '' said Charleston County spokeswoman Tracey Amick . `` Our car had water coming through the doors . It 's ridiculous right now . There are trash cans floating down the street , cars stuck , people trying to get through these flooded streets on bicycles . '' The tropical moisture , combined with a trough of low pressure off the coast , prompted a flash-flood warning in the city that was to continue until 12:30 a.m. Wednesday . About 20 vehicles were stranded on streets at one time , said meteorologist Vern Beaver of the National Weather Service . Heavy flooding also was reported in Mount Pleasant and North Charleston . The College of Charleston reported 5 inches of rainfall by 7 p.m. Tuesday . West Ashley reported 7.5 inches , as did Daniel Island . Significant flooding was reported near the Historic Charleston City Market . The worst of the flooding appeared over late Tuesday , forecasters said . Senior forecaster Steven Taylor said most of the rain Tuesday afternoon fell during low tide . Winds were pushing slightly above normal tides in downtown Charleston . `` If we get heavy rain to fall during high tide , the flooding level will only increase , '' he said . Beaver expected rain to continue into Thursday , although it wo n't be as heavy as Tuesday 's downpour . Preparing for a storm : Links , tips and resources . CNN 's Nick Valencia and Phil Gast contributed to this report , .
Forecasters worried about rain during high tide . Isaac contributes to heavy rains in coastal South Carolina . Motorists stranded on Charleston streets .