The closure, which began about 9:30 p.m. Tuesday, extended from Warner Avenue south to Seapoint Street, near the Bolsa Chica Ecological Reserve. It was unclear when PCH would be reopened.
Flooding also bedeviled a Huntington Beach neighborhood near Beach Boulevard and the 405 Freeway, where at least one family scrambled to sweep water out of their home.
A 90 percent chance of showers is expected Wednesday evening in Orange County, where a flash flood watch was issued by the National Weather Service. New rains could bring between one-quarter and one-half of an inch of precipitation. The flood watch is scheduled to expire at 6 p.m. Thursday.
In Long Beach's Belmont Shore area, floodwaters were deep enough to submerge sidewalks on some streets. Long Beach Public Works crews were summoned overnight to clear out clogged storm drains.