The Coast Guard set out to airlift 30 tons of emergency food supplies into snowbound Cincinnati yesterday. Local officials said it might be the first such disaster-relief operation in U.S. history.

The food airlift, coordinated by the Agriculture Department, involved moving 60,000 pounds of basic commodities to Cincinnati from a Army warehouse in Minnesota aboard two Coast Guard transport planes.

"We've been told this is the first time anything like this has been done in this country," said Charles Black, a spokesman for the Cincinnati Red Cross, which requested the relief. "Apparently this stuff is always available but no one ever asked for it before."

Vital foodstuffs have been running dangerously low throughout Ohio since the state was buried by a killer-blizzard that paralyzed the entire Middle West last week.

Black said the supplies included powdered milk and eggs, canned fruit and vegetables, rice and infant formula and would be delivered to snow-bound homes in and around Cincinnati by four-wheel-drive emergency vehicles.

Thousands of refugees from the "blizzard of 78" remained hold up in emergency rescue centers throughout Indiana and Ohio, the two states hit hardest by the storm, but progress was reported throughout the Midwest in road-clearing and rescue operations.

About 300 Army troops and 30 pieces of equipment were airlifted into northwestern Ohio to help the National Guard and local officials dig out those still stranded by what Gov. James Rhodes described as the worst blizzard ever to hit the state.

The troops also used helicopters to bring vital supplies to persons in remote areas. Many highways and roads remained clogged with the up to 18 inches of snow that buried parts of the state, and the unofficial casualty count rose to at lest 19.

Lt. Gen. John W. Morris, chief of the Army Corps of Engineers, flew to Cincinnati to inspect ice problems clogging the Ohio River between Plittsburgh and Louisville.

About 100 barges were reported loose in the river between the two cities and threatening damage to the locks and dams.

Highway officials in Illitiois, where at least 20 persons were killed in the inslaught of snow and wind, reported all major roads passable but slippery in some sections.