From the Washington suburbs to the Pennsylvania line, tens of thousands of Marylanders shivered with no electricity yesterday while others struggled to clear downed trees and branches and the governor declared a state of emergency in six counties.

Just before midnight last night, Baltimore Gas and Electric Co. reported that 75,000 customers were still without power.

At its peak, more than 332,000 customers -- 119,000 in the Baltimore area -- lost electric service as tree limbs weighted with melting ice toppled across power lines, forcing BGE to summon out-of-state crews for the first time in almost two decades.

Schools closed, shelters opened and hospital emergency rooms overflowed throughout Central Maryland.

Pat Miller, a volunteer running a shelter at Owings Mills High School, said there were 11 people there last night.

"We've got two families with children, several folks from an assisted living facility and one lady came in by herself," Miller said. "They've got hot meals, snacks, cots, blankets and just a warm place to be."

Others resorted to a more expensive shelter: Many hotels and motels in the area were fully booked.

"I remember the ice storm of 1994. This is certainly as big as that one," said Butch Kinerney, a spokesman for the Maryland Emergency Management Agency, which coordinates statewide responses to disasters.

As Maryland went from frozen to partially thawed yesterday, Gov. Parris N. Glendening issued an emergency declaration for Baltimore,Carroll, Harford, Howard, Montgomery and Prince George's counties.

Despite a forecast for temperatures rising into the upper 40s today, state officials were poised to mobilize the National Guard to handle power outages expected to last into next week, particularly in the hard-hit Washington suburbs.

"We're not calling the National Guard out in force, but we're using some of their personnel to deliver dry ice, man stoplights and move people to shelters," Kinerney said.

"This gives us the flexibility over the three-day weekend to call them in at any time."

GE distributed dry ice at the Towson Armory, the Mall in Columbia and the Carrolltowne Shopping Center yesterday afternoon and planned to reopen those centers today at 8 a.m.

The storm's aftermath filled some hospital emergency rooms with victims of falls and minor traffic accidents, forced one Howard County group home for the elderly to evacuate its residents, and sent road salt and ice-melting products winging out of area hardware stores as fast as deliveries were received.

Government offices operated with skeleton crews. A lack of energy closed the U.S. Department of Energy complex outside Gaithersburg.

Police officers, firefighters, utility workers, road crews and cable television technicians worked throughout the day and into the evening.

In Baltimore, Carroll and Howard counties, highways were mostly clear but many secondary roads looked as if they had been mulched. Bits of wood and broken branches littered miles of pavement. Motorists also contended with a steady pelting of melting ice falling from trees and power lines.

For many residents, things got worse as the day wore on.

"We woke up at 5: 30, no power -- scrambled around for a flashlight," said Barbara Nolan, a resident of the 1600 block of Landon Road in Towson. At mid-morning, she and her children heard a cracking sound in the back yard and found a weeping willow tree, uprooted by the weight of melting ice, lying "like so much lace, ice-covered and gone."

Dallas Tucker, who lives with his wife in the 3500 block of Rolling Road, had an equally troublesome morning. "No electricity since midnight," he said, taking a break from hand sawing an 8-foot tree limb that had blocked his driveway.

Long weekend

With the Martin Luther King Jr. holiday coming up Monday, many Maryland schoolchildren wound up with a five-day weekend after the storm canceled classes Thursday and yesterday.

In Montgomery and Prince George's counties and the District of Columbia, the storm left 213,000 PEPCO customers without electricity. Three-quarters of those outages were in Montgomery.

Although additional crews were expected from New Jersey and South Carolina today, a PEPCO spokeswoman said the utility might not be able to restore power to everyone until Tuesday.

Under the emergency order issued by the governor last night, the state suspended rules for commercial drivers so that out-of-state power company trucks could enter Maryland quickly without stopping at weigh stations to complete time-consuming paperwork.

PEPCO was bringing in 40 crews from out of state, Kinerney said.

Police officers with flashlights and flares replaced darkened traffic signals at many major intersections in Southern Maryland, and county officials estimated that signals were out at 300 crossroads.

In Baltimore County, yellow-coated county officers steered motorists away from roads closed by downed trees, and police estimated that at least two dozen major intersections were without traffic signals all day.

Record day in the ER

In Rockville, the emergency room at Shady Grove Adventist Hospital recorded its busiest day ever Thursday, treating 264 people for fractures, dislocations and neck and back injuries.

"It was pretty intense. We had staff from all over the hospital pitch in," said hospital spokesman Robert Jepson. "You have to be ready for any circumstance, but it's not something we'd like to repeat."

With temperatures expected to fall into the 20s last night, shelters began opening in most of the affected counties. "I think the greatest fear is that the power won't come on," said Victoria Goodman, Howard County spokeswoman.

"We've got a lot of seniors here," said Donna Evans, a recreation aide at the East County Recreation Center in Silver Spring. Turned into an emergency shelter, the center took in 35 people last night.

"The Red Cross is here with food, the cots are on the way," Evans said.

In Baltimore City, falling branches cut off power as fast as workers restored it.

"We repair and another one comes down again," said Karl Neddenien, a BGE spokesman. "It's happening enough to make this a very difficult job."

Scattered power outages also were reported in Anne Arundel County, with the Severna Park-Pasadena area hardest hit.

"We started getting calls around 8 o'clock, mostly limbs down across lines to individual homes and a few which knocked out neighborhoods," said BGE spokesman Mike Delaney.

Damage to trees