For thousands of Virginia and District children, summer vacation ended yesterday on an unusually soggy note as the early morning school bell was drowned out by heavy downpours.

But rain-caused transportation delays and flooding in outlying counties were only a couple of the problems faced by some returning students.

At T.C. Williams High School in Alexandria, 2,238 students were evacuated when the electricity was shut off after a frayed underground wire overheated, and school officials feared a fire or explosion might result. About 900 students went home on buses routed to the school for the evacuation, while most of the rest waited under an outdoor overhang for family members, friends and taxis to take them home.

"Everyone was packed in trying to stay dry," said Roy Hollins, 16, who said meeting new people is the best part of any new school year. "It's drearier than last year," said Hollins. "It's supposed to be fun, pepped up."

Michael Johnson, an underground lineman for Virginia Power, said a 20-year-old, cloth-covered wire leading from the building's main power transformer short-circuited. He said the faulty line will be replaced.

Principal John Porter, making his way through the school's pitch-black hallways yesterday, said school will reopen today.

"The kids were beautiful, considering the rain," said Porter, who had announced the evacuation during fourth period, about 10:20 a.m. "They were excited about getting another day of vacation."

School officials throughout the region were busy yesterday counting heads and dealing with rain-related problems, which were particularly troublesome in outlying counties.

Schools closed early in Culpeper, Greene and Madison counties. Flooding occurred in Fauquier County, and officials there had to find alternative bus routes to get students home.

Minor transportation delays were reported in Arlington County, where the failure of the school system's main administrative computers added to the day's frustrations.

School officials said the weather probably dampened enrollment figures.

In Fairfax County, 131,000 students showed up for classes, 2,500 more than last year. About 98,000 students were expected to show up for classes in the District, a marginal increase over last year.

In Prince William County, 37,636 students were enrolled, about 360 fewer than predicted. In Arlington, 13,603 students attended school, 1,048 fewer than expected. Alexandria recorded about 8,872, roughly 500 below predictions.

At Key Elementary School in Arlington, where school officials feared crowding would be a problem, fewer students than expected showed up. Principal Paul Wireman said renovations at the Lee Gardens apartment complex, which has forced many low-income Hispanic families to move, may have made the difference.

In Alexandria, officials were pleased at the high, 228-student enrollment at Barrett Elementary School. Last year, parents successfully lobbied the school board to keep the school open, regardless of low enrollment figures.

However, enrollment figures were not on the minds of the pupils and parents.

Jennifer Saffelle, a 7-year-old at Arlington's Key school, said she was so excited about starting school that she had a hard time sleeping Monday night. "My mom woke me up and I jumped out of bed. Then I was looking for my special pants," explained Jennifer, who said her new stone-washed jeans were the end-all in first-day school fashion.

At Douglas MacArthur Elementary School in Alexandria, 10-year-old George Dowell said he was pleased with his first day. "You meet the teachers and you meet new people, new friends," he said.

At a nearby table sat Alexandria's new superintendent, Paul Masem, who stopped by to have lunch with his 11-year-old son Eli, after having visited seven schools in the morning. Masem has said he intends to visit a different school each week.

Staff writer Alice Digilio contributed to this report.