Lights go out. Computers crash. Flights are delayed, baggage is lost. ATMs run out of cash, cellular calls won't go through and cable TV is showing static.

Sound like the nation's worst Y2K fears? In the increasingly complex world of technology, those disasters can occur individually all in a day's work--whether or not that day is the coming New Year's.

Concerned that any technical failure in the earliest hours of Jan. 1 will be blamed on the Year 2000 computer problem, the White House plans to release figures today showing how often some systems typically break down.

The move is precautionary, to avert public panic at the first sign of a disruption in electricity or another essential service that may coincide with the date rollover but one not caused by the computer glitch.

Some failures may take weeks of study before Y2K can be blamed or dismissed as the cause.

"Every day, things go wrong, and nobody pays much attention to them, nobody thinks twice about it," said John Koskinen, President Clinton's top Y2K adviser. "But any of those things that happen on January 1st will immediately be presumed to be the indication of a Y2K problem."

Even though the nation's electrical utilities are rated more than 99 percent reliable, winter storms can darken neighborhoods and entire regions. Koskinen puts odds at 50-50 that a major ice storm or blizzard will strike America during that critical New Year's weekend.

In 1989, for example, a failed switch shut down electricity on New Year's Eve for 90,000 citizens in Maine.

The Washington-based Edison Electric Institute said in a report for the White House that any power failure over the Jan. 1 weekend "is almost certain to have occurred because of one of the usual reasons" rather than the Y2K bug.

"We have interruptions in the power grid all the time," said Sen. Robert F. Bennett (R-Utah), chairman of the Senate's Special Committee on the Year 2000 Technology Problem. "We have interruptions in the flow of oil around the world all the time. We have all kinds of accidents that take place in computerland, and those that happen on January 1st, people will say were caused by Y2K."

Computers and their programming code are at the heart of the Year 2000 problem, over which devices that aren't sufficiently tested or repaired could misinterpret the year "00" as 1900. That could corrupt important electronic records, miscalculate utility bills and interest rates, or cause a variety of havoc with automated systems.

But software already is so enormously complex that computers sometimes fail for many other reasons. Microsoft Corp., whose Windows software runs most of the world's personal computers, fields about 29,000 phone calls daily from customers using more than 4,000 programs, who complain that their PCs aren't working right.

Consumer Internet connections over phone lines can be infamously feeble, and even the most popular Web destinations experience crashes. Hackers routinely vandalize Web sites that have poor security, frequently attacking dozens of high-profile targets over a holiday weekend.

The government has assured travelers that airlines in the United States will be safe, though it has also warned of possible delays and lost baggage.

The most recent figures from the Federal Aviation Administration show that only four of every five flights of the nation's largest carriers arrive on schedule, and that for every 1,000 passengers, more than four temporarily lose their luggage en route. That translated into nearly 185,000 mishandled pieces in October.

About 10 percent of all credit transactions fail routinely because equipment breaks down or consumers are overextended or forget their ATM password, said Paul Schmelzer, an executive vice president for Orlando-based Star Systems Inc., which process about 2 billion financial transactions annually. He expects those same problems to show up on New Year's.

Koskinen said government officials will be looking to see whether the problems detected exceed what is expected. And he noted that it won't be immediately obvious what caused each of the problems.

"The focus of the people whose systems aren't working will be to get the systems working," he said. "You're not going to be quite as focused on whether this is Y2K or not."