The people of this small lakeside town, placed squarely in the path of radioactive winds from the Chernobyl nuclear plant, are slowly discovering the fright they never knew when the crisis struck here last Monday.

By scientific standards, a storm of lethal radioactive iodine blew in here Monday morning, wreaking unknown and perhaps incalculable damage on Mikolajki's 3,500 people. Yet as they anxiously think back on that day, all residents can remember is that the weather was beautiful, with brilliant sunshine and crisp spring breezes. Though there were rumors of trouble, nothing unusual happened in the town.

Polish government experts have since told western reporters that the radiation here was 500 times greater than normal Monday and as much as six times above the accepted international daily safety standard. But Polish media available here censored the news, and shops, schools and even ice cream vendors have been working normally. Children were encouraged to turn out for yesterday's local May Day parade.

Only the military helicopters that have been shuttling equipment and experts to a nearby weather station -- and the unsettling sense of nausea that many say they are feeling -- have hinted at the blow suffered by the town, which lies about 400 miles northwest of the Soviet reactor site. And it is precisely that sinister calm, say some residents, that has made the last days so difficult to bear.

"Everyone is worried, but no one knows what to do," said a 23-year-old woman who operates a small vegetable stand in the center of Mikolajki (pronounced mee-koh-wai-kee). "We know it was bad here even if no one said so. We can feel it."

Several persons here said in interviews that headaches and feelings of nausea have been widespread among the population in the last two days. School officials said many children had been absent from classes, and others had visited nurses complaining of headaches and stomachaches.

Government officials, while saying the symptoms cannot be linked to radiation, have distributed doses of sodium iodide to children and some adults and have banned the sale of milk from grass-fed cows. Radiation experts working at the local meteorological institute have conveyed another potent warning by withdrawing their own children from school and sending them out of town.

Yet the practical difficulties of battling an invisible threat have pushed many uneasily back to old routines. In the rolling, grassy hills around Mikolajki, farmers were grazing their cows again today despite government orders to use dry fodder.

"My wife and daughter told me to keep the cows in, but what can I do -- I don't have enough feed in storage," said farmer Jozef Tyminski as he grazed his cows by a roadside today. "Certainly I'm worried about the radiation, but there's only so much I can do."

The surreal mixture of fear and seeming normality has been common around Poland this week. On Wednesday afternoon, there were scenes of panic in Warsaw as families lined up at health clinics to obtain the iodine doses belatedly made available by authorities to the country's 11 million children under age 16. Yet the next morning, tens of thousands turned out for an official May Day parade and opposition counterdemonstrations.

Polish experts appointed to a special government commission told western reporters at a press conference yesterday that they expected an increase in cancer rates as a result of the radiation. The news was censored from the national media, however, and a communique today from the same commission said "no danger existed to the health of the population."

In Washington, State Department spokesman Charles Redman said women of childbearing age and children should not travel to Poland "until the situation is clarified." The Polish government had recommended such an action, he said.

In Mikolajki, which the government commission said recorded the highest radiation readings in Poland, official accounts appear equally ambiguous. Two government radiation experts, including commission member Zbigniew Jaworowski, confirmed today that the radiation level of 2.5 milliroentgen per hour recorded here Monday would have been six times above the normal safety standard, which is based on a period of 24 hours.

Jaworowski said in a telephone interview, however, that the radiation level was well below an international standard for danger levels in "emergency situations," which is based on a period of 10 days of radiation absorption. He said the symptoms reported by residents could have been induced by anxiety.

Though uninformed of the figures, residents said rumors of extremely high radiation levels spread quickly from the state meteorological compound here Monday. Yet because no official announcement of the Chernobyl accident and its dangers had been made either in Poland or the Soviet Union, few took the stories seriously.

"At first people thought the equipment had broken down," said Maria, an office worker who heard early Monday of the high radiation readings. "Then no one wanted to believe it. It was like a big joke until Tuesday, when they announced about the radiation in Warsaw and the military came here in their helicopter. By then, it was already too late for us."

The Army helicopters are still coming, setting down at least once a day on a grassy field near the meteorology compound. Technicians quickly take samples of soil and earth from the field and measure air radiation with small gauges, then board the helicopters and depart.

Today, one of the technicians could be seen hurriedly scooping up soil with special protective gloves as children who had been playing nearby crowded around to watch.

"Those people, the scientists who have sent their own children out of here, are obviously the best informed," a resident said. "But we, the simple people of Mikolajki, we're stuck here, for better or for worse. There's no way to escape your shadow. There's no way we can escape what happened here."