WASHINGTON — Hurricane Katrina, by forcing an exodus of workers and families from New Orleans and surrounding areas, appears likely to rank alongside Sept. 11 and the Arab oil embargo of 1973 as one of the nation's most serious and sudden economic shocks — particularly in terms of job losses — in recent memory.

Before the storm, the Mobile, Ala., Biloxi, Miss., and New Orleans metropolitan areas supported about 1 million non-farm jobs, with about 600,000 in New Orleans alone. Analysts at Stone & McCarthy Research Associates estimated yesterday that the storm has wiped out several hundred thousand jobs along the Gulf of Mexico coast, at least temporarily. "It seems almost as if a nuclear weapon went off in New Orleans," said George Friedman, chairman of Strategic Forecasting Inc. "The displacement of the population is the crisis that New Orleans faces. It is also a national crisis, because the largest port in the United States cannot function without a city around it. The physical and business processes of a port cannot occur in a ghost town, and right now, that is what New Orleans is."

The only people remaining in the city yesterday predominantly were emergency aid workers, law enforcement officers and people waiting to be evacuated. The workforce that once operated the region's oil rigs, refineries and other businesses is now widely dispersed. The result could be a labor force crisis that delays recovery.

By comparison, in recent years, the biggest one-month drop in the U.S. national job-count occurred when 377,000 employees lost work in October 2001, after the Sept. 11 terrorist attacks. And the last time more than 600,000 jobs were lost nationally was in December 1974, during the recession that followed the 1973 oil embargo.

Soon after Katrina hit, surging gasoline prices were already prompting consumers to curtail their spending on other items. That may cause businesses to cut back on hiring and investment, likely slowing economic growth in coming months. The slump's severity will depend critically on consumer psychology, analysts said yesterday: A panicky response to climbing gas prices would help drive them up higher, making things worse.

"This disaster is unleashing the type of energy supply shock that we had viewed as the economy's greatest vulnerability," William Dudley, of Goldman, Sachs & Co. said yesterday.

Katrina's impact on the economy will worsen if rising gas prices cause employers to hold off hiring or to cut jobs because of slowing demand, weakening the national labor market.

The hurricane hit as the U.S. economy was rolling along at full steam, little affected by oil prices that had roughly doubled in the last two years to around $65 a barrel and gasoline prices that had topped $2 a gallon nationally. Consumer and business spending was rising and employers were adding jobs at a healthy clip. The Labor Department reported yesterday that the nation's unemployment rate fell to 4.9 percent last month, the lowest level in four years.

Many economists expect Katrina's effects to slow economic growth for several months, but to be followed eventually by a reconstruction boom in the Gulf states.