Fresh cloudbursts yesterday brought more record flooding to southeast Texas and renewed peril along Mississippi's Pearl River, while the Air Force flew sandbags to the inundated Red River Valley in the upper Midwest.

And at least four tornadoes touched down in Louisiana, including a twister that demolished the Crawfish Festival midway in Chalmette and injured two persons lightly.

Louisiana's torrential weather over the weekend also claimed at least one life, a 6-year-old boy who drowned in a rain-swollen Baton Rouge bayou.

With towns such as Columbia, Miss., East Grand Forks, Minn., and Beaumont, Tex., still under serious threat, the toll in property damage from this spring's unusual flooding continued to grow.

Mississippi Gov. Cliff Finch estimated the bill at between $900 million and $1 billion in his state. An estimated 23,000 residents along the Pearl River were forced to flee.

Burt Bratcher of the Texas Civil Defense placed the damage from flooding since Wednesday at $100 million in Harris County and $50 million to $75 million in Conroe, about 50 miles north of Houston. The floods also have claimed at least four lives in Texas.

In the endangered Pearl River town of Columbia, where about half the 8,000 residents had already abandoned their homes, Mayor Robert Bourne ordered schools closed, told merchants to keep only minimum numbers of clerks in their stores and asked residents to stay home.

The National Weather Service said torrential rains that soaked southwest Mississippi and south-central Louisiana with 5.6 inches of rain within 24 hours were expected in the Pearl River basin and could produce flash flooding.

To add to the area's woes, high winds or tornadoes felled trees across power lines in two other south Mississippi towns and a tornado watch was posted in the Columbia area.

Columbia was spared more severe damage Friday when the road bed of U.S. 98, the main east-west highway, was cut to let the water through. The Pearl dropped slightly.

But Bourne said yesterday the fresh rains would likely bring higher waters, perhaps as far as the court-house in the town's main square.

The Houston-Beaumont-Conroe areas of southeast Texas have received a total of 12 inches of rain since Wednesday and the National Weather Service said most streams were well over flood stage yesterday, with the Neches River nearing a record crest at Beaumont.

In the Midwest, the Air Force flew 450,000 sandbags to East Grand Forks, Minn., where volunteers were fighting to hold back the raging Red River, and another 460,000 bags were on their way from Offut Air Force Base in Nebraska.

Bill Owen, a Civil Defense spokesman, said two workers helping shore up the dikes suffered minor injuries and were taken by boat to United Hospital in Gran Forks, which was surrounded by water 3 to 5 feet deep.

The National Weather Service said the river at East Grand Forks was at 48.48 feet and still rising yesterday, more than 20 feet over the flood stage of 28 feet.

The Louisiana twisters also touched at such scattered locations as Lafayette, Hammond and Belle Chasse. No major damage or serious injuries were reported.

But another tornado Saturday near New Iberia caused more than $500,000 in damage.At least two persons were hospitalized, neither in serious condition. CAPTION: Picture, A resident of Grand Forks, N.D., waits atop garage roof of townhouse for rescue boat. Water levels in some streets of the subdivision reached 15 feet. AP Picture, Sandbags line storefronts in Columbia, Miss., at to win braces for flooding from the Pearl River. UPI