SEATTLE -- Waters flooding Interstate 5 in Lewis County appeared to be receding slightly at midday Wednesday, but the main north-south highway connecting the Puget Sound area with Portland remained closed. The soonest it could open would be after the weekend, officials said.

Chopper 7 pilot Clark Stahl said it appeared the rivers had crested and water levels in Lewis County "have gone down a little bit," but widespread damage was left in the flood's wake.

Transportation officials told KIRO 7 Eyewitness News they are waiting for water levels to recede before they can assess how much damage I-5 has suffered.

Flood warnings remained in effect for many rivers in the region, but the National Weather Service said they're on their way down. The Chehalis River at Centralia is forecast to recede below flood stage early Wednesday night.

Forecasters said they expect cooler, drier weather for the rest of the week as thousands in Western Washington are trying to clean up flood damage from a powerful series of storms that killed at least five people and brought a deluge of 3 to 6 inches of rain.

Gov. Chris Gregoire said helicopter crews have rescued 300 people from flooded areas of Western Washington this week and the operation is continuing.

The storm is blamed for at least five deaths and carbon monoxide poisoning that 19 people sick at a Ocean Shores grocery store. Two fatalities were reported Monday afternoon in Grays Harbor County, a third man was killed in Mason County on Monday night when a building was hit by a mudslide. On Tuesday morning, rescuers found an injured man and the bodies of two hikers who disappeared near Snow Lake near the Alpental ski area in the Alpine Lakes Wilderness area of Snoqualmie Pass. They were killed by an avalanche.

Divers plan to search a creek near Winlock where officials fear Richard Hiatt, 81, fell into the water and was swept away while he was checking the outflow from a sump pump Monday when the creek bank collapsed.

The Pierce County sheriff's office said a search for three snowboarders missing near Crystal Mountain is delayed because of dangerous conditions. An aerial search may be launched later Wednesday if conditions improve. The men went snowboarding in the backcountry on Friday and were reported overdue on Monday.

VIDEO: Chopper 7 Pilot Clark Stahl Tours Flood Damage
VIDEO: I-5 To Remain Closed Throughout Weekend
VIDEO: National Guardsmen Going Door-To-Door In Mason County

In Grays Harbor County, crews repaired a Bonneville Power Administration feeder line early Wednesday, restoring power to most of Aberdeen. Officials said outlying areas in the county may remain in the dark for a few more days.

Numerous school districts in Grays Harbor County are closed Wednesday. Get the complete list of school closures in Western Washington here.

Pe Ell School District officials told KIRO 7 Eyewitness News its schools would remain closed the rest of this week.

Some residents of Mason County are still stranded by high waters. A rescue effort is being launched by officials.

In Kitsap County, officials asked residents with storm damage to report it by using the county's Web site or by calling 360-307-5870.