Flooding is expected along the Youghiogheny, Monongahela and Ohio rivers from Confluence to Downtown Pittsburgh to Wheeling, W.Va., over the next several days, the National Weather Service said Thursday.

A rapid snow melt combined with up to 2 inches of rain will cause the rivers to rise rapidly, the weather service said in a flood advisory issued shortly after noon.

The Mon Wharf parking lot was expected to flood this morning and will be closed. More serious flooding is expected along the rivers Saturday through Monday.

The weather service was forecasting a crest of 26.5 feet at the Point on Sunday, which would flood the 10th Street Bypass, Parkway East, North Shore riverwalk and some low-lying residential and commercial areas along the rivers.

"That number could change," meteorologist Rodney Smith said, depending on how much rain falls.

Pittsburgh Mayor Luke Ravenstahl, who toured flood-prone sections of the North Side, Esplen and Duck Hollow near Squirrel Hill on Thursday, said weather forecasters told the city the crest might go as high as 32 feet. That would be within two feet of the January 1996 flood, considered one of the worst in Pittsburgh history.

"I hope the skeptics are right," Mr. Ravenstahl said as he walked a stretch of River Avenue that was under water in 1996. "Nothing would make me happier than to wake up Monday morning and know I wasted Friday and Saturday."

Firefighters fanned out in high-risk areas to distribute leaflets warning residents of possible evacuations as early as Saturday. The city has made arrangements to open five shelters if needed, Public Safety Chief Michael Huss said.

Weather service projections Thursday called for the Mon to exceed flood stage at Braddock, Elizabeth and Charleroi on Sunday.

The weather service issued a flood warning for the Youghiogheny near Confluence and Connellsville starting this evening. It said moderate flooding is forecast as the river rises to near 14.8 feet. Flood stage is 14 feet.

Major flooding was forecast along the Youghiogheny at Sutersville and West Newton late Saturday or early Sunday.

The Ohio River is expected to surpass flood stage Sunday into Monday as far away as Powhatan Point, Ohio, downstream of Wheeling.

The source of the flood concerns was a heavy snow pack in the mountains from the snowiest month in the region's recorded history.

In Garrett County, Md., which feeds the headwaters of the Yough, forecasters estimated that the unmelted snow held the equivalent of 10 inches of rain.

On Pittsburgh's North Shore, the Rivers Casino was readying sandbags outside on Thursday "purely as a precaution," spokesman Jack Horner said.

The casino, with 3,000 electronic slot machines, could be heavily damaged if floodwaters reach the building, but Mr. Horner said officials, after consulting with the city, were not expecting that.

"All indications are that this water is not coming up that high. But with Mother Nature being somewhat unpredictable, we decided to err on the side of caution," he said.

The Army Corps of Engineers, which operates 16 flood-control reservoirs across the district, issued a statement on Thursday "to dispel rumors" that the Yough River Lake reservoir was full and unable to receive and hold runoff.

"For the past 10 days, Youghiogheny River Lake has released water at a higher rate to allow for additional storage and to compensate for the rise in the water level expected from the large snow pack this year," the statement said.

As of Thursday morning, 13 of the 16 reservoirs had used 5 percent or less of their flood storage capacity.

"All of the Army Corps' 16 flood damage reduction reservoirs are well-positioned to capture forecasted runoff and precipitation," the agency said.

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