When Joseph McGowan's alarm goes off at 3:45 a.m. and he peers out his window, more than 11,000 Alexandria children and their parents will be affected by what he sees.

For the past 15 winters, it's been up to McGowan to decide whether the weather warrants closing Alexandria schools.

"You have to be a little crazy to do this job," he admitted. "But I love it."

Each Northern Virginia school system has a detailed plan of action that goes into effect when even the rumors of a snowflake are reported. And though the final decision to close or not to close usually lies with school superintendents, the process demands quick thinking by dozens of people who have been on double duty during the snows of the last few weeks.

"It's always a lousy decision to have to make," said Alexandria Superintendent Robert W. Peebles. "All you can do is make the most intelligent one."

The decision-making process on snow emergencies varies from one school district to another. Fairfax County uses a complex network of two-way radios. In Falls Church, Superintendent Warren J. Pace sometimes takes to the streets on days when a decision could go either way. But as Bill Shadle, assistant superintendent for general services in Fairfax County, said, "We are only really interested in one thing: the safety of the kids."

For McGowan, it all begins with the 11 p.m. weather report.

"If the weather looks bad for the next day, I'll set the alarm for about 3:45 a.m.," said McGowan. After an initial inspection of what, if anything, has accumulated on the redwood porch outside his window, McGowan said, he dresses in his walk-in closet so as not to disturb his sleeping wife, downs a glass of orange juice, jumps into his car and immediately switches on the radio.

By 4:15, McGowan is heading for roads heavily traveled by Alexandria school buses. He goes east on Duke Street, tests Braddock Hill and heads off to Quaker Lane. "Then I head for the city maintenance shop, where I check the Accu-Weather ticker and talk to the foreman in charge. I see how their trucks are doing and, if I've noticed any problems on my run over, I tell them and they promise to hit it."

"On my way home from there, I usually decide what I'm going to do," said McGowan, who by this time has spent about an hour testing road conditions and mulling the weather forecast for the next few hours.

But several other factors complicate the decision. Because in many families no parent is home during the day, a decision to call off school creates a child-care problem for many parents. And since the city uses Metrobuses to transport secondary school students, a decision to open schools several hours late often makes it impossible on such short notice to get the needed buses at the later time.

McGowan also tries to coordinate with neighboring school districts, listening for other school-closing announcements on the radio and sometimes talking to their officials. On a tough call, he telephones Peebles for consultation.

By the time he gets home, he has made up his mind. Whether the decision is to close or open, McGowan calls the city's transportation specialist, the woman who calls the substitute teachers and more than 20 radio and TV stations and wire services who will broadcast the decision.

Only then can he go back to bed for a few more winks, before getting ready to be at his regular job, as the school system's purchasing agent, by 8:15.

"Once I make the decision, I have to live with it," said McGowan. "I do get all kinds of calls from parents, but it's hard to please everybody."

McGowan and his counterparts at other school districts are among the most hated and most loved persons in Northern Virginia, depending on the day.

"Sure, I'm always getting calls from kids asking me to close the schools," said Robert Devers, director of transportation for Loudoun County schools, who makes the closing decisions with the help of the Dulles weather bureau and a staff scattered around the county's 500 square miles. "We are over 95 percent rural and we have flat areas to foothills."

The job is especially difficult, Devers said, on days when snow is forecast but none is on the ground by 5:30 a.m., his decision deadline. "Sometimes I come out of the house and it's kind of like the old groundhog on Groundhog's Day," he joked.

Prince William and Fairfax counties also have a lot of ground to cover before they make a decision. "Some mothers and fathers just look at their house or their street and complain about the decision," said Robert Grimes, an associate superintendent in Prince William. "They don't realize that I am looking at the whole county."

Even in Arlington, conditions differ in various parts of the county, which George Allin, director of auxiliary services for transportation, must drive through between 4 and 5 a.m. before he can make his closing recommendation to the superintendent.

There, as in other jurisdictions, either all schools close or none do.

In Fairfax, Bill Shadle, who sits by his phone on snowy mornings and gathers all road condition information from key people around the county, sometimes has a seven-day work week. "Last Saturday, I had to cancel 66 field trips and had to make the awesome decision of canceling the SAT testing," he said.

In Falls Church, Superintedent Warren J. Pace normally gathers information from key transportation and school staff--but he recently hopped on a school bus for an early morning ride with Transportation Supervisor Robert Major to assess the conditions firsthand.

"It's a difficult decision," admitted Pace. "And sometimes it's a no-win situation. . . . You just have to make the judgment on the best possible information you have at the time."